Price Risk Management [Abstract]
Price Risk Management [Abstract]
PRICE RISK MANAGEMENT
Derivative Instruments and Hedging Activities Disclosure [Text Block]
Additional Fair Value Elements [Abstract]
Fair Value Option, Disclosures [Table]
Fair Value Option, Disclosures [Table]
Fair Value Hierarchy and NAV [Axis]
Fair Value Hierarchy and NAV [Axis]
Fair Value Hierarchy and NAV [Domain]
Fair Value Hierarchy and NAV [Domain]
Fair Value, Inputs, Level 2 [Member]
Fair Value, Inputs, Level 2 [Member]
Fair Value, Inputs, Level 3 [Member]
Fair Value, Inputs, Level 3 [Member]
Measurement Frequency [Axis]
Measurement Frequency [Axis]
Fair Value, Measurement Frequency [Domain]
Fair Value, Measurement Frequency [Domain]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers, Net
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers, Net
Cash Surrender Value, Fair Value Disclosure
Cash Surrender Value, Fair Value Disclosure
Long-term Debt
Long-term Debt
Unamortized Debt Issuance Expense
Unamortized Debt Issuance Expense
Long-term Debt, Fair Value
Long-term Debt, Fair Value
Condensed Consolidated Balance Sheets (Unaudited) (Parentheticals) [Abstract]
Condensed Consolidated Balance Sheets (Unaudited) (Parentheticals) [Abstract]
Statement [Table]
Statement [Table]
Scenario [Axis]
Scenario [Axis]
Scenario, Unspecified [Domain]
Scenario, Unspecified [Domain]
Class of Stock [Axis]
Class of Stock [Axis]
Class of Stock [Domain]
Class of Stock [Domain]
Statement [Line Items]
Statement [Line Items]
Preferred stock, no par value
Preferred Stock, No Par Value
Preferred stock, shares authorized
Preferred Stock, Shares Authorized
Preferred stock, issued
Preferred Stock, Shares Issued
Preferred stock, outstanding
Preferred Stock, Shares Outstanding
Common stock, no par value
Common Stock, No Par Value
Common stock, shares authorized
Common Stock, Shares Authorized
Common stock, shares issued
Common Stock, Shares, Issued
Common stock, shares outstanding
Common Stock, Shares, Outstanding
Income Tax Disclosure [Abstract]
Federal statutory tax rate
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent
Federal tax credits
Effective Income Tax Rate Reconciliation, Tax Credit, Percent
State and local taxes, net of federal tax benefit
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent
Flow through depreciation and cost basis differences
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Depreciation, Percent
Excess deferred tax amortization
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Depletion, Percent
Other
Effective Income Tax Rate Reconciliation, Other Adjustments, Percent
Effective tax rate
Effective Income Tax Rate Reconciliation, Percent
Derivative, by Nature [Axis]
Derivative Instrument [Axis]
Derivative, Name [Domain]
Derivative Contract [Domain]
Natural Gas [Member]
Natural Gas [Member]
4911 Electric Services [Member]
4911 Electric Services [Member]
Liabilities, Total [Member]
Liabilities, Total [Member]
Derivative Instruments and Hedges, Liabilities
Derivative Instruments and Hedges, Liabilities
Derivative Liability, Collateral, Right to Reclaim Cash, Offset
Derivative Liability, Collateral, Right to Reclaim Cash, Offset
Net gain or (loss) recognized in the statement of income offset by regulatory accounting
Net gain or loss recognized in the statement of income offset by regulatory accounting
Net gain or loss recognized in the statement of income for derivative instruments related to price risk management activities offset by regulatory accounting.
Derivative, Net Liability Position, Aggregate Fair Value
Derivative, Net Liability Position, Aggregate Fair Value
Collateral Already Posted, Aggregate Fair Value
Collateral Already Posted, Aggregate Fair Value
Collateral cash requirement
Collateral Aggregate Fair Value
The aggregate fair value of assets that would be required to be posted as collateral for derviative instruments with credit-risk-related contingent features if the credit-risk-related contingent features were triggered at the end of the reporting period.
Deposit Assets
Deposit Assets
Derivative Liability
Derivative Liability
Income Statement [Abstract]
Revenue, net
Revenue from Contract with Customer, Including Assessed Tax
Alternative revenue programs, net of amortization
Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Change in Estimate of Transaction Price
Total Revenues
Revenues
Operating expenses:
Costs and Expenses [Abstract]
Purchased power and fuel
Utilities Operating Expense, Purchased Power
Generation, transmission and distribution
Utilities Operating Expense, Maintenance and Operations
Administrative and other
General and Administrative Expense
Depreciation and amortization
Depreciation, Depletion and Amortization
Taxes other than income taxes
Taxes, Miscellaneous
Total operating expenses
Costs and Expenses
Income from operations
Operating Income (Loss)
Interest expense, net
Interest Expense
Other income:
Other Income and Expenses [Abstract]
Allowance for equity funds used during construction
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity
Miscellaneous income, net
Other Nonoperating Income (Expense)
Other income, net
Nonoperating Income (Expense)
Income before income tax expense
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest
Income tax expense
Income Tax Expense (Benefit)
Net income
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest
Other Comprehensive Income
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax
Comprehensive Income
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest
Weighted-average common shares outstanding (in thousands):
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Basic
Weighted Average Number of Shares Outstanding, Basic
Diluted
Weighted Average Number of Shares Outstanding, Diluted
Earnings per share:
Earnings Per Share [Abstract]
Basic
Earnings Per Share, Basic
Diluted
Earnings Per Share, Diluted
Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table]
Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table]
Balance Sheet Location [Axis]
Balance Sheet Location [Axis]
Balance Sheet Location [Domain]
Balance Sheet Location [Domain]
Derivatives, Fair Value [Line Items]
Derivatives, Fair Value [Line Items]
Current assets:
Assets, Current [Abstract]
Current Assets, Commodity Contracts:
Current Assets, Commodity Contracts: [Abstract]
Commodity contracts: [Abstract]
Electricity
Commodity Contract Asset, Current, Electricity
Carrying amount as of the balance sheet date of the asset arising from commodity contracts related to electricity which are expected to be settled within a year or normal operating cycle, if longer.
Natural gas
Commodity Contract Asset, Current, Natural Gas
Carrying amount as of the balance sheet date of the asset arising from commodity contracts related to natural gas which are expected to be settled within a year or normal operating cycle, if longer.
Total current derivative assets
Current Derivative Assets
Fair valules as of the balance sheet date for all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments, and which are expected to be settled within one year or the normal operating cycle, if longer.
Noncurrent assets:
Assets, Noncurrent [Abstract]
Noncurrent Assets, Commodity Contracts: [Abstract]
Noncurrent Assets, Commodity Contracts: [Abstract]
Noncurrent Assets, Commodity Contracts: [Abstract]
Total derivative assets not designated as hedging instruments
Price Risk Derivative Instruments Not Designated as Hedging Instruments Asset, at Fair Value
Total derivative assets
Derivative Assets, Total
Fair values as of the balance sheet date of all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments.
Current liabilities:
Liabilities, Current [Abstract]
Current Liabilities, Commodity Contracts: [Abstract]
Current Liabilities, Commodity Contracts: [Abstract]
Electricity
Commodity Contract Liability, Current, Electricity
Carrying amount as of the balance sheet date of the liability arising from commodity contracts related to electricity which are expected to be settled within a year or the normal operating cycle, if longer.
Natural gas
Commodity Contract Liability, Current, Natural Gas
Carrying amount as of the balance sheet date of the liability arising from the commodity contracts related to natural gas which are expected to be settled within a year or normal operating cycle, if longer.
Total current derivative liabilities
Current Derivative Liabilities
Fair values as of the balance sheet date for all liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments, and which are expected to be settled within one year of the normal operating cycle, if longer.
Noncurrent liabilities:
Liabilities, Noncurrent [Abstract]
Noncurrent Liabilities, Commodity Contracts: [Abstract]
Noncurrent Liabilities, Commodity Contracts: [Abstract]
Electricity
Commodity Contract Liability, Noncurrent, Electricity
Carrying amount as of the balance sheet date of the liability arising from commodity contracts related to electricity which are expected to be settled after a year or beyond the normal operating cycle, if longer.
Natural gas
Commodity Contract Liability, Noncurrent, Natural Gas
Carrying amount as of the balance sheet date of the liability arising from commodity contracts related to natural gas which are expected to be settled after a year or beyond the normal operating cycle, if longer.
Total noncurrent derivative liabilities
Noncurrent Derivative Liabilities
Fair values as of the balance sheet date for all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments, and which are expected to be settled after one year or normal operating cycle, if longer.
Total derivative liabilities not designated as hedging instruments
Price Risk Derivative Instruments Not Designated as Hedging Instruments Liability, at Fair Value
Total derivative liabilities
Derivative Liabilities, Total
Fair values as of the balance sheet date of all liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.
Commodity Contract Asset, Noncurrent, Electricity
Commodity Contract Asset, Noncurrent, Electricity
Carrying amount as of the balance sheet date of the asset arising from commodity contracts related to electricity which are expected to be settled after a year or beyond the normal operating cycle, if longer.
Commodity Contract Asset, Noncurrent, Natural Gas
Commodity Contract Asset, Noncurrent, Natural Gas
Carrying amount as of the balance sheet date of the asset arising from commodity contracts related to natural gas which are expected to be settled after a year or beyond the normal operating cycle, if longer.
Derivative Asset, Noncurrent
Derivative Asset, Noncurrent
Leases [Abstract]
Capital Leases, Future Minimum Payments Due, Next Twelve Months
Capital Leases, Future Minimum Payments Due, Next Twelve Months
Contractual Obligation, Due in Next Fiscal Year
Contractual Obligation, Due in Next Fiscal Year
Operating Leases, Future Minimum Payments Due, Next Twelve Months
Operating Leases, Future Minimum Payments Due, Next Twelve Months
Capital Leases, Future Minimum Payments Due in Two Years
Capital Leases, Future Minimum Payments Due in Two Years
Contractual Obligation, Due in Second Year
Contractual Obligation, Due in Second Year
Operating Leases, Future Minimum Payments, Due in Two Years
Operating Leases, Future Minimum Payments, Due in Two Years
Capital Leases, Future Minimum Payments Due in Three Years
Capital Leases, Future Minimum Payments Due in Three Years
Contractual Obligation, Due in Third Year
Contractual Obligation, Due in Third Year
Operating Leases, Future Minimum Payments, Due in Three Years
Operating Leases, Future Minimum Payments, Due in Three Years
Capital Leases, Future Minimum Payments Due in Four Years
Capital Leases, Future Minimum Payments Due in Four Years
Contractual Obligation, Due in Fourth Year
Contractual Obligation, Due in Fourth Year
Operating Leases, Future Minimum Payments, Due in Four Years
Operating Leases, Future Minimum Payments, Due in Four Years
Capital Leases, Future Minimum Payments Due in Five Years
Capital Leases, Future Minimum Payments Due in Five Years
Contractual Obligation, Due in Fifth Year
Contractual Obligation, Due in Fifth Year
Operating Leases, Future Minimum Payments, Due in Five Years
Operating Leases, Future Minimum Payments, Due in Five Years
Capital Leases, Future Minimum Payments Due Thereafter
Capital Leases, Future Minimum Payments Due Thereafter
Contractual Obligation, Due after Fifth Year
Contractual Obligation, Due after Fifth Year
Operating Leases, Future Minimum Payments, Due Thereafter
Operating Leases, Future Minimum Payments, Due Thereafter
Capital Leases, Future Minimum Payments Due
Capital Leases, Future Minimum Payments Due
Contractual Obligation
Contractual Obligation
Operating Leases, Future Minimum Payments Due
Operating Leases, Future Minimum Payments Due
Capital Leases, Future Minimum Payments, Interest Included in Payments
Capital Leases, Future Minimum Payments, Interest Included in Payments
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments
Capital Lease Obligations, Current
Capital Lease Obligations, Current
Purchase Commitment, Remaining Minimum Amount Committed
Purchase Commitment, Remaining Minimum Amount Committed
Derivative [Table]
Derivative [Table]
Derivative [Line Items]
Derivative [Line Items]
Commodity contracts:
Electricity
Realized and Unrealized Gains and Losses, Net, Commodity Contracts, Electricity
Realized and unrealized gains and losses, net on commodity contracts related to electricity not designated as hedging instruments included in purchased power and fuel expense in the statement of income.
Natural Gas
Realized and Unrealized Gains and Losses, Net, Commodity Contracts, Natural Gas
Realized and unrealized gains and losses, net on commodity contracts related to natural gas not designated as hedging instruments included in purchased power and fuel expense in the statement of income.
Foreign currency exchange
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments
Fair Value of Financial Instruments [Abstract]
Fair Value of Financial Instruments [Abstract]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance as of the beginning of the period
Net Liabilities From Price Risk Management Activities Classified As Level 3
Net Liabilities From Price Risk Management Activities Classified as Level 3
Net realized and unrealized (gains)/losses
Realized and Unrealized Gains and Losses, Net, Commodity Contract
Realized and Unrealized Gains and Losses, Net, Commodity Contracts
Transfers out of Level 3 to Level 2
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3
Balance as of the end of the period
Lessee, Leases [Policy Text Block]
Lessee, Leases [Policy Text Block]
Weighted Average Number of Shares Outstanding, Basic
Dilutive effect of potential common shares
Weighted Average Number Diluted Shares Outstanding Adjustment
Weighted Average Number of Shares Outstanding, Diluted
Revenue Recognition and Deferred Revenue [Abstract]
Disaggregation of Revenue [Table Text Block]
Disaggregation of Revenue [Table Text Block]
Revenue Recognition, Multiple-deliverable Arrangements, Description [Policy Text Block]
Revenue Recognition, Multiple-deliverable Arrangements, Description [Policy Text Block]
Other Current Liabilities [Abstract]
Other Current Liabilities [Abstract]
Other Current Liabilities [Table]
Other Current Liabilities [Table]
Other Current Liabilities [Table]
Accrued employee compensation and benefits
Employee-related Liabilities, Current
Accrued taxes payable
Taxes Payable, Current
Accrued interest payable
Interest Payable
Accrued dividends payable
Dividends Payable, Current
Regulatory liabilities—current
Regulatory Liability, Current
Other
Other Current Liabilities - Other
Other Current Liabilities - Other
Total accrued expenses and other current liabilities
Other Liabilities, Current
Contingencies [Abstract]
Contingencies [Abstract]
CONTINGENCIES
Commitments and Contingencies Disclosure [Text Block]
Operating Lease, Right-of-Use Asset
Operating Lease, Right-of-Use Asset
Operating Lease, Liability, Current
Operating Lease, Liability, Current
Operating Lease, Liability, Noncurrent
Operating Lease, Liability, Noncurrent
Operating Lease, Liability
Operating Lease, Liability
Finance Lease, Right-of-Use Asset
Finance Lease, Right-of-Use Asset
Finance Lease, Liability, Current
Finance Lease, Liability, Current
Finance Lease, Liability Noncurrent
Finance Lease, Liability, Noncurrent
Finance Lease, Liability
Finance Lease, Liability
Derivative Instrument [Axis]
Derivative Contract [Domain]
Electricity [Member]
Electricity [Member]
Net Unrealized Loss [Member]
Unrealized Gain Loss On Derivatives [Member]
Unrealized Gain Loss On Derivatives [Member]
Schedule of Future Expected Realized Gains or Losses [Axis]
Schedule of Future Expected Realized Gains or Losses [Axis]
Schedule of Future Expected Realized Gains or Losses [Domain]
Schedule of Future Expected Realized Gains or Losses [Domain]
2019
Other Commitment, Due in Next Twelve Months
2020
Other Commitment, Due in Second Year
2021
Other Commitment, Due in Third Year
2022
Other Commitment, Due in Fourth Year
2023
Other Commitment, Due in Fifth Year
Thereafter
Other Commitment, Due after Fifth Year
Total
Other Commitment
Fair Value Measurements, Recurring and Nonrecurring [Table]
Fair Value Measurements, Recurring and Nonrecurring [Table]
Fair Value, Measurements, Fair Value Hierarchy [Domain]
Fair Value, Inputs, Level 1 [Member]
Fair Value, Inputs, Level 1 [Member]
Assets:
Assets [Abstract]
Cash equivalents
Cash and Cash Equivalents, Fair Value Disclosure
Nuclear decommissioning trust: (1)
Nuclear decommissioning trust: [Abstract]
Nuclear decommissioning trust: [Abstract]
Debt securities:
Debt Securities [Abstract]
Domestic government
US Government Securities, at Carrying Value
Corporate credit
Financial Instruments, Owned, Corporate Debt, at Fair Value
Money market funds measured at NAV (2)
Money Market Funds, at Carrying Value
Non-qualified benefit plan trust: (2)
Nonqualified Benefit Plan Trust: [Abstract]
Non-qualified benefit plan trust: [Abstract]
Money market funds
Fair Value - Money market funds
Fair Value - Money market funds
Equity securities - domestic
Mutual Funds, Equity
Equity mutual fund assets held in the Non-qualified benefit plan trust, which are carried at fair value.
Debt securities—domestic government
Mutual Funds, Debt
Debt mutual funds assets in the Non-qualified benefit plan trust, which are carried at fair value.
Assets from price risk management activities: (1) (3)
Assets from price risk management activities: [Abstract]
Assets from price risk management activities: [Abstract]
Electricity
Commodity Contract Asset, Electricity
Carrying amount as of the balance sheet date of the asset arising from commodity contracts related to purchases or sales of electricity.
Natural gas
Commodity Contract Asset, Natural gas
Carrying amount as of the balance sheet date of the asset arising from commodity contracts related to purchases or sales of natural gas.
Total
Financial Instruments, Owned, at Fair Value
Assets, Fair Value Disclosure
Assets, Fair Value Disclosure
Liabilities from price risk management activities: (1) (3)
Liabilities from price risk management activities: [Abstract]
Liabilities from price risk management activities: [Abstract]
Electricity
Commodity Contract Liabilities, Electricity
Carrying amount as of the balance sheet date of the liabilities arising from commodity contracts related to purchases or sales of electricity.
Natural gas
Commodity Contract Liabilities, Natural gas
Carrying amount as of the balance sheet date of the liabilities arising from commodity contracts related to purchases or sales of natural gas.
Total
Financial and Nonfinancial Liabilities, Fair Value Disclosure
Balance Sheet Components [Abstract]
Balance Sheet Components [Abstract]
Schedule of Defined Benefit Plans Disclosures [Table]
Schedule of Defined Benefit Plans Disclosures [Table]
Retirement Plan Type [Axis]
Retirement Plan Type [Axis]
Retirement Plan Type [Domain]
Retirement Plan Type [Domain]
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Disclosure [Line Items]
Service cost
Defined Benefit Plan, Service Cost
Interest cost
Defined Benefit Plan, Interest Cost
Expected return on plan assets
Defined Benefit Plan, Expected Return (Loss) on Plan Assets
Amortization of net actuarial loss
Defined Benefit Plan, Amortization of Gain (Loss)
Net periodic benefit cost
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year
Finance Lease, Liability, Payments, Remainder of Fiscal Year
Finance Lease, Liability, Payments, Remainder of Fiscal Year
Lessee, Operating Lease, Liability, Payments, Due Year Two
Lessee, Operating Lease, Liability, Payments, Due Year Two
Finance Lease, Liability, Payments, Due Year Two
Finance Lease, Liability, Payments, Due Year Two
Lessee, Operating Lease, Liability, Payments, Due Year Three
Lessee, Operating Lease, Liability, Payments, Due Year Three
Finance Lease, Liability, Payments, Due Year Three
Finance Lease, Liability, Payments, Due Year Three
Lessee, Operating Lease, Liability, Payments, Due Year Four
Lessee, Operating Lease, Liability, Payments, Due Year Four
Finance Lease, Liability, Payments, Due Year Four
Finance Lease, Liability, Payments, Due Year Four
Lessee, Operating Lease, Liability, Payments, Due Year Five
Lessee, Operating Lease, Liability, Payments, Due Year Five
Finance Lease, Liability, Payments, Due Year Five
Finance Lease, Liability, Payments, Due Year Five
Lessee, Operating Lease, Liability, Payments, Due after Year Five
Lessee, Operating Lease, Liability, Payments, Due after Year Five
Finance Lease, Liability, Payments, Due after Year Five
Finance Lease, Liability, Payments, Due after Year Five
Lessee, Operating Lease, Liability, Payments, Due
Lessee, Operating Lease, Liability, Payments, Due
Finance Lease, Liability, Payments, Due
Finance Lease, Liability, Payments, Due
Lessee, Operating Lease, Liability, Undiscounted Excess Amount
Lessee, Operating Lease, Liability, Undiscounted Excess Amount
Finance Lease, Liability, Undiscounted Excess Amount
Finance Lease, Liability, Undiscounted Excess Amount
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table]
Credit Facility [Axis]
Credit Facility [Axis]
Credit Facility [Domain]
Credit Facility [Domain]
Letter of Credit [Member]
Letter of Credit [Member]
Extinguishment of Debt [Axis]
Extinguishment of Debt [Axis]
Extinguishment of Debt, Type [Domain]
Extinguishment of Debt, Type [Domain]
SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis]
SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis]
SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain]
SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Letters of Credit Outstanding, Amount
Letters of Credit Outstanding, Amount
Finite-Lived Intangible Assets, Accumulated Amortization
Finite-Lived Intangible Assets, Accumulated Amortization
Amortization of Intangible Assets
Amortization of Intangible Assets
Line of Credit Facility, Maximum Borrowing Capacity
Line of Credit Facility, Maximum Borrowing Capacity
Debt Instrument, Covenant Description
Debt Instrument, Covenant Ratio
Debt Instrument, Covenant Ratio
Ratio of Indebtedness to Net Capital
Ratio of Indebtedness to Net Capital
Short-term debt
Short-term Debt
Commercial Paper
Commercial Paper
Line of Credit Facility, Remaining Borrowing Capacity
Line of Credit Facility, Remaining Borrowing Capacity
Line of Credit Facility, Current Borrowing Capacity
Line of Credit Facility, Current Borrowing Capacity
Letters of credit issued
Pledged Financial Instruments, Not Separately Reported, Securities for Letter of Credit Facilities
Authorized Short-Term Debt
Authorized Short-Term Debt
FERC-authorized short-term debt through February 6, 2012
Long-term Debt, Current Maturities
Long-term Debt, Current Maturities
Proceeds from Issuance of Long-term Debt
Proceeds from Issuance of Long-term Debt
Other Current Assets [Table]
Other Current Assets [Table]
Other Current Assets [Table]
Other Current Assets [Line Items]
other current assets [Line Items] [Line Items]
other current assets [Line Items] [Line Items]
Prepaid expenses
Prepaid Expense and Other Assets, Current
Assets from price risk management activities
Regulatory assets from price risk management activities
Regulatory assets from price risk management activities
Margin deposits
Margin Deposit Assets
Other Assets, Miscellaneous
Other Assets, Miscellaneous
Other current assets
Other Assets, Current
Disaggregation of Revenue [Table]
Disaggregation of Revenue [Table]
Regulatory Liability [Axis]
Regulatory Liability [Axis]
Regulatory Liability [Domain]
Regulatory Liability [Domain]
Revenue Subject to Refund [Member]
Revenue Subject to Refund [Member]
Product and Service [Axis]
Product and Service [Axis]
Product and Service [Domain]
Product and Service [Domain]
Residential [Member]
Residential [Member]
Residential [Member]
Commercial [Member]
Commercial [Member]
Commercial [Member]
Industrial [Member]
Industrial [Member]
Industrial [Member]
Direct Access customers [Member]
Direct Access customers [Member]
Direct Access customers [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue [Line Items]
Subtotal
Regulated Operating Revenue, Electric, Non-Nuclear
Net tax benefits due to the change in tax rate under the TCJA
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount
Other accrued (deferred) revenues, net
Deferred Revenue, Revenue Recognized
Total retail revenues
Regulated Operating Revenue
Wholesale revenues
Unregulated Operating Revenue
Other operating revenue
Regulated and Unregulated Operating Revenue
Gain on Derivative Instruments, Pretax
Gain on Derivative Instruments, Pretax
Lease Cost [Table Text Block]
Lease, Cost [Table Text Block]
Supplemental Information [Table Text Block]
Leases of Lessee Disclosure [Text Block]
Lease Term and Discount Rate [Table Text Block]
Lessee, Operating Lease, Liability, Maturity [Table Text Block]
Maturities of Lease Liabilities [Table Text Block]
Schedule of Future Minimum Lease Payments for Capital Leases [Table Text Block]
Supplemental Cash Flow Information [Table Text Block]
Schedule of Cash Flow, Supplemental Disclosures [Table Text Block]
Future Minimum Lease Payments [Table Text Block]
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]
BALANCE SHEET COMPONENTS
Details of Certain Balance Sheet Accounts Disclosure [Text Block]
Details of Certain Balance Sheet Accounts
Revenue Recognition, Multiple-deliverable Arrangements [Table Text Block]
Revenue Recognition, Multiple-deliverable Arrangements [Table Text Block]
Guarantees [Abstract]
GUARANTEES
Guarantees [Text Block]
Schedule of Other Current Assets [Table Text Block]
Schedule of Other Current Assets [Table Text Block]
Schedule of Public Utility Property, Plant, and Equipment [Table Text Block]
Public Utility Property, Plant, and Equipment [Table Text Block]
Schedule of Regulatory Assets and Liabilities [Text Block]
Schedule of Regulatory Assets and Liabilities [Text Block]
Other Liabilities Disclosure [Text Block]
Other Liabilities Disclosure [Text Block]
Pension and Other Postretirement Benefits Disclosure [Text Block]
Pension and Other Postretirement Benefits Disclosure [Text Block]
Concentration Risk [Table]
Concentration Risk [Table]
Concentration Risk Type [Axis]
Concentration Risk Type [Axis]
Concentration Risk Type [Domain]
Concentration Risk Type [Domain]
Concentration Risk [Line Items]
Concentration Risk [Line Items]
Assets from price risk management activities:
Counterparty A
Counterparty-A
Individually significant counterparty of total assets arising from derivative instruments from price risk management activities.
Counterparty B
Counterparty B
Individually significant counterparty of total assets arising from derivative instruments from price risk management activities.
Concentration of Risk, Derivative Instruments, Assets
Concentration of Risk, Derivative Instruments, Assets
Represents aggregate of individually significant counterparties of total assets arising from derivative instruments from price risk management activities.
Liabilities from price risk management activities:
Counterparty C
Concentration of Risk, Derivative Instruments, Liabilities
Represents aggregate of individually significant counterparties of total liabilities arising from derivative instruments from price risk management activities.
Deferred Tax Assets, Operating Loss Carryforwards, Domestic
Deferred Tax Assets, Operating Loss Carryforwards, Domestic
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount
Unrecognized Tax Benefits
Unrecognized Tax Benefits, Income Tax Penalties Accrued
Operating Lease, Payments
Operating Lease, Payments
Variable Lease, Cost
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability
Incremental Common Shares Attributable to Dilutive Effect of Contingently Issuable Shares
Incremental Common Shares Attributable to Dilutive Effect of Contingently Issuable Shares
Basis of Presentation [Abstract]
Basis of Presentation [Abstract]
Consolidation, Policy [Policy Text Block]
Consolidation, Policy [Policy Text Block]
Inventory, Policy [Policy Text Block]
Inventory, Policy [Policy Text Block]
Debt, Policy [Policy Text Block]
Debt, Policy [Policy Text Block]
Fair Value of Financial Instruments, Policy [Policy Text Block]
Fair Value of Financial Instruments, Policy [Policy Text Block]
Allocation of Financial Asset to Hierarchy Levels [Policy Text Block]
Allocation of Financial Asset to Hierarchy Levels [Policy Text Block]
Allocation of Financial Asset to Hierarchy Levels [Policy Text Block]
Fair Value Transfer, Policy [Policy Text Block]
Fair Value Transfer, Policy [Policy Text Block]
Derivatives, Policy [Policy Text Block]
Derivatives, Policy [Policy Text Block]
Commitments and Contingencies, Policy [Policy Text Block]
Commitments and Contingencies, Policy [Policy Text Block]
Guarantees, Indemnifications and Warranties Policies [Policy Text Block]
Guarantees, Indemnifications and Warranties Policies [Policy Text Block]
FAIR VALUE OF FINANCIAL INSTRUMENTS
Fair Value Disclosures [Text Block]
Schedule of Property, Plant and Equipment [Table]
Property, Plant and Equipment [Table]
Property, Plant and Equipment, Type [Axis]
Property, Plant and Equipment, Type [Axis]
Property, Plant and Equipment, Type [Domain]
Property, Plant and Equipment, Type [Domain]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment [Line Items]
Electric utility plant
Public Utilities, Property, Plant and Equipment, Plant in Service
Construction work-in-progress
Public Utilities, Property, Plant and Equipment, Construction Work in Progress
Total cost
Property, Plant and Equipment, Gross
Less: accumulated depreciation and amortization
Public Utilities, Property, Plant and Equipment, Accumulated Depreciation
Electric utility plant, net
Public Utilities, Property, Plant and Equipment, Net
Statement of Stockholders' Equity [Abstract]
Common Stock, Dividends, Per Share, Declared
Common Stock, Dividends, Per Share, Declared
Service Area Sq Miles
Service Area Sq Miles
Approximate square miles of service area.
Incorporated Cities
Incorporated Cities
Number of incorporated cities in service area.
Number of Retail Customers
Number of Retail Customers
Includes residential, commercial and industrial.
Percent of state population
Percent of State's Population
Service area population as a percent of the state's population.
Change in Accounting Estimate by Type [Axis]
Change in Accounting Estimate by Type [Axis]
Change in Accounting Estimate, Type [Domain]
Change in Accounting Estimate, Type [Domain]
Accounting Standards Update 2016-02 [Member]
Accounting Standards Update 2016-02 [Member]
Building [Member]
Building [Member]
Assets Held under Capital Leases [Member]
Assets Held under Capital Leases [Member]
Property, Plant and Equipment [Member]
Property, Plant and Equipment [Member]
Equity Components [Axis]
Equity Components [Axis]
Equity Component [Domain]
Equity Component [Domain]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification
Defined Benefit Plan, Non-service Cost
Reclassification of stranded tax effects due to Tax Reform
Reclassification of stranded tax effects due to Tax Reform
Reclassification of stranded tax effects due to Tax Reform
Disclosure Text Block [Abstract]
Lessee, Finance Leases [Text Block]
EARNINGS PER SHARE
Earnings Per Share [Text Block]
Equity [Abstract]
Equity
Stockholders' Equity Note Disclosure [Text Block]
Income Tax Disclosure [Text Block]
Income Tax Disclosure [Text Block]
Schedule of Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Table]
Schedule of Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Table]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
Loss Contingencies [Table]
Loss Contingencies [Table]
Loss Contingency Nature [Axis]
Loss Contingency Nature [Axis]
Loss Contingency, Nature [Domain]
Loss Contingency, Nature [Domain]
Range [Axis]
Range [Axis]
Range [Domain]
Range [Domain]
Minimum [Member]
Minimum [Member]
Loss Contingencies [Line Items]
Loss Contingencies [Line Items]
Site Contingency, Names of Other Potentially Responsible Parties
Number Of Potentially Responsible Parties
Number Of Potentially Responsible Parties
Litigation Settlement, Expense
Litigation Settlement, Expense
Loss Contingency, Estimate of Possible Loss
Loss Contingency, Estimate of Possible Loss
Loss Contingency, Damages Sought, Value
Loss Contingency, Damages Sought, Value
Loss Contingency, Range of Possible Loss, Portion Not Accrued
Loss Contingency, Range of Possible Loss, Portion Not Accrued
Environmental Remediation Expense
Environmental Remediation Expense
Investment in Trojan
investment in Trojan
The portion of the Company's remaining investment in its Trojan plant that the OPUC allowed the Company to recover.
Class action damages sought
Class action lawsuit damages sought
Class action lawsuit damages sought by plaintiffs against the Company.
Price Risk Management Note [Abstract]
Price risk management note.
Electricity
Volume Related to Derivative Instruments Held at Balance Sheet Date, Commodity Contracts, Electricity
Net volume related to the reporting entity's derivative instruments as of the balance sheet date having arisen from price risk management activities.
Natural gas
Volume Related to Derivative Instruments at Balance Sheet Date, Commodity Contracts, Natural Gas
Net volume associated with the reporting entity's derivative instruments recorded as of the balance sheet date having arisen from price risk management activities related to natural gas.
Foreign currency
Volume Related to Derivative Instruments Held at Balance Sheet Date, Foreign Currency
Net amount associated with the reporting entity's derivative instruments recorded as of the balance sheet date having arisen from price risk management activities related to foreign currency.
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]
Eligible Item or Group for Fair Value Option [Axis]
Financial Instrument [Axis]
Fair Value, Option, Eligible Item or Group [Domain]
Financial Instruments [Domain]
Assets [Member]
Assets [Member]
Liabilities [Member]
Derivative Financial Instruments, Liabilities [Member]
Low [Member]
High [Member]
Maximum [Member]
Weighted Average [Member]
Weighted Average [Member]
Commodity Contracts
Fair Value, Option, Quantitative Disclosures [Line Items]
Electricity physical forwards
Electricity physical forward purchase
Electricity physical forward purchase
Natural gas financial swaps
Natural gas financial swaps
Natural gas financial swaps
Financial swaps - electricity
Fnancial swaps - electricity
Fnancial swaps - electricity
Total commodity contracts
Total commodity contracts
Total commodity contracts
Accounting Changes and Error Corrections [Abstract]
Schedule of Changes for Adoption of New Accounting Pronouncements [Table Text Block]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]
Fair Value Option, Disclosures [Table Text Block]
Fair Value Option, Disclosures [Table Text Block]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]
New Accounting Pronouncements or Change in Accounting Principle [Table]
New Accounting Pronouncements or Change in Accounting Principle [Table]
Other Noncurrent Assets [Member]
Other Noncurrent Assets [Member]
Accrued Liabilities [Member]
Other Current Liabilities [Member]
Other Noncurrent Liabilities [Member]
Other Noncurrent Liabilities [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification
Common Stock [Member]
Common Stock [Member]
Common Stock Including Additional Paid in Capital [Member]
AOCI Attributable to Parent [Member]
Retained Earnings [Member]
Common Stock, Shares, Outstanding beginning of period
Issuances of shares pursuant to equity-based plans
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures
Issuance of shares pursuant to equity-based plans
Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options
Adjustments Related to Tax Withholding for Share-based Compensation
Adjustments Related to Tax Withholding for Share-based Compensation
Stockholders' Equity
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest
Stock-based compensation
Share-based Compensation
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent
Dividends declared
Dividends, Common Stock
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest
Reclassification of stranded tax effects due to Tax Reform
Common Stock, Shares, Outstanding end of period
Stockholders' Equity
BASIS OF PRESENTATION
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]
Operating Lease, Liability
Present value of future operating lease payments
Present value of additional operating lease payments for agreements that have not yet commenced.
Capital Leased Assets, Gross
Capital Leased Assets, Gross
Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation
Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation
Capital Lease Obligations, Current
Deferred Costs, Leasing, Accumulated Amortization
Deferred Costs, Leasing, Accumulated Amortization
Interest Expense, Lessee, Assets under Capital Lease
Interest Expense, Lessee, Assets under Capital Lease
Long-term Purchase Commitment, Amount
Long-term Purchase Commitment, Amount
Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress
Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress
Operating Leases, Rent Expense
Operating Leases, Rent Expense
Operating Leases, Rent Expense, Contingent Rentals
Operating Leases, Rent Expense, Contingent Rentals
Operating Leases, Rent Expense, Sublease Rentals
Operating Leases, Rent Expense, Sublease Rentals
Statement of Cash Flows [Abstract]
Cash flows from operating activities:
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net income
Adjustments to reconcile net income to net cash provided by operating activities:
Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Deferred income taxes
Deferred Income Tax Expense (Benefit)
Pension and other postretirement benefits
Pension and Other Postretirement Benefits Cost (Reversal of Cost)
Allowance for equity funds used during construction
Decoupling mechanism deferrals, net of amortization
Decoupling Mechanism Deferrals, Net
The deferral, which can be either a positive or negaitive amount depending on whether a collection from or refund to customers results, of the amounts recorded in net income for energy useage by customers on a weather adjusted basis that is different from base rates as determined under the Company's decoupling mechanism, expected to be recovered or refunded in future periods.
(Amortization) Deferral of net benefits due to Tax Reform
Tax Adjustments, Settlements, and Unusual Provisions
Other non-cash income and expenses, net
Other Noncash Income (Expense)
Changes in working capital:
Increase (Decrease) in Operating Capital [Abstract]
Decrease in accounts receivable and unbilled revenues
Increase (Decrease) in Receivables
(Increase) in inventories
Increase (Decrease) in Inventories
Decrease in margin deposits, net
Increase (Decrease) in Margin Deposits Outstanding
(Decrease) in accounts payable and accrued liabilities
Increase (Decrease) in Accounts Payable
Other working capital items, net
Increase (Decrease) in Other Operating Assets and Liabilities, Net
Other, net
Increase (Decrease) in Other Operating Assets
Net cash provided by operating activities
Net Cash Provided by (Used in) Operating Activities
Cash flows from investing activities:
Net Cash Provided by (Used in) Investing Activities [Abstract]
Capital expenditures
Payments to Acquire Property, Plant, and Equipment
Sales of Nuclear decommissioning trust securities
Proceeds from Sale, Maturity and Collection of Investments
Purchases of Nuclear decommissioning trust securities
Payments to Acquire Investments
Other, net
Payments for (Proceeds from) Other Investing Activities
Net cash used in investing activities
Net Cash Provided by (Used in) Investing Activities
Cash flows from financing activities:
Net Cash Provided by (Used in) Financing Activities [Abstract]
Payments of Long-term Debt
Repayments of Long-term Debt
Issuance of Commercial Paper, net
Proceeds from (Repayments of) Commercial Paper
Dividends paid
Payments of Dividends
Other
Proceeds from (Payments for) Other Financing Activities
Net cash used in financing activities
Net Cash Provided by (Used in) Financing Activities
(Decrease) increase in cash and cash equivalents
Cash and Cash Equivalents, Period Increase (Decrease)
Cash and cash equivalents, beginning of period
Cash and Cash Equivalents, at Carrying Value
Cash and cash equivalents, end of period
Supplemental cash flow information is as follows:
Supplemental Cash Flow Information [Abstract]
Cash paid for interest, net of amounts capitalized
Interest Paid, Excluding Capitalized Interest, Operating Activities
Cash paid for income taxes
Income Taxes Paid
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]
Schedule of Derivative Instruments [Table Text Block]
Schedule of Derivative Instruments [Table Text Block]
Derivatives Not Designated as Hedging Instruments [Table Text Block]
Derivatives Not Designated as Hedging Instruments [Table Text Block]
Schedule of Price Risk Derivatives [Table Text Block]
Schedule of Price Risk Derivatives [Table Text Block]
Schedule of Concentration of Risk, by Counterparty [Table Text Block]
Schedules of Concentration of Risk, by Risk Factor [Table Text Block]
Cover page.
Document Type
Document Type
Document Quarterly Report
Document Quarterly Report
Document Period End Date
Document Period End Date
Document Transition Report
Document Transition Report
Entity File Number
Entity File Number
Entity Registrant Name
Entity Registrant Name
Entity Incorporation, State or Country Code
Entity Incorporation, State or Country Code
Entity Tax Identification Number
Entity Tax Identification Number
Entity Address, Address Line One
Entity Address, Address Line One
Entity Address, City or Town
Entity Address, City or Town
Entity Address, State or Province
Entity Address, State or Province
Entity Address, Postal Zip Code
Entity Address, Postal Zip Code
City Area Code
City Area Code
Local Phone Number
Local Phone Number
Title of 12(b) Security
Title of 12(b) Security
Trading Symbol
Trading Symbol
Security Exchange Name
Security Exchange Name
Entity Current Reporting Status
Entity Current Reporting Status
Entity Interactive Data Current
Entity Interactive Data Current
Entity Filer Category
Entity Filer Category
Entity Small Business
Entity Small Business
Entity Emerging Growth Company
Entity Emerging Growth Company
Entity Shell Company
Entity Shell Company
Entity Common Stock, Shares Outstanding
Entity Common Stock, Shares Outstanding
Entity Central Index Key
Entity Central Index Key
Amendment Flag
Amendment Flag
Document Fiscal Year Focus
Document Fiscal Year Focus
Document Fiscal Period Focus
Document Fiscal Period Focus
Current Fiscal Year End Date
Current Fiscal Year End Date
Schedule of Stockholders Equity [Table Text Block]
Schedule of Stockholders Equity [Table Text Block]
Statement of Financial Position [Abstract]
ASSETS
Cash and cash equivalents
Accounts receivable, net
Accounts Receivable, Net, Current
Unbilled revenues
Unbilled Receivables, Current
Inventories
Energy Related Inventory
Regulatory assets - current
Regulatory Assets, Current
Other current assets
Total current assets
Assets, Current
Electric utility plant, net
Regulatory assets - noncurrent
Regulatory Assets, Noncurrent
Nuclear decommissioning trust
Decommissioning Fund Investments
Non-qualified benefit plan trust
Assets Held-in-trust, Noncurrent
Other noncurrent assets
Other Assets, Noncurrent
Total assets
Assets
LIABILITIES AND EQUITY
Liabilities and Equity [Abstract]
Current liabilities
Accounts payable
Accounts Payable, Current
Liabilities from price risk mangement activities - current
Derivative Liability, Current
Current portion of long-term debt
Accrued expenses and other current liabilities
Total current liabilities
Liabilities, Current
Long-term debt, net of current portion
Long-term Debt, Excluding Current Maturities
Regulatory liabilities-noncurrent
Regulatory Liability, Noncurrent
Deferred income taxes
Deferred Tax Liabilities, Net, Noncurrent
Unfunded status of pension and postretirement plans
Liability, Defined Benefit Plan, Noncurrent
Liabilities from price risk management activities-noncurrent
Derivative Liability, Noncurrent
Asset retirement obligations
Asset Retirement Obligation
Non-qualified benefit plan liabilities
Liability, Other Postretirement Defined Benefit Plan, Noncurrent
Finance lease obligations, net of current portion
Other noncurrent liabilities
Other Liabilities, Noncurrent
Total liabilities
Liabilities
Commitments and contingencies (see notes)
Commitments and Contingencies
Shareholders' Equity:
Preferred stock, no par value, 30,000,000 shares authorized; none issued and outstanding as of June 30, 2019 and December 31, 2018
Preferred Stock, Value, Issued
Common stock, no par value, 160,000,000 shares authorized; 89,371,560 and 89,267,959 shares issued and outstanding as of June 30, 2019 and December 31, 2018, respectively
Common Stock, Value, Issued
Accumulated other comprehensive loss
Accumulated Other Comprehensive Income (Loss), Net of Tax
Retained earnings
Retained Earnings (Accumulated Deficit)
Total shareholders' equity
Total liabilities and shareholders' equity
Liabilities and Equity
Schedule of Regulatory Assets [Table]
Schedule of Regulatory Assets [Table]
Regulatory Asset [Axis]
Regulatory Asset [Axis]
Regulatory Asset [Domain]
Regulatory Asset [Domain]
Deferred Derivative Gain (Loss) [Member]
Deferred Derivative Gain (Loss) [Member]
Pension and Other Postretirement Plans Costs [Member]
Pension and Other Postretirement Plans Costs [Member]
Loss on Reacquired Debt [Member]
Loss on Reacquired Debt [Member]
Environmental Restoration Costs [Member]
Environmental Restoration Costs [Member]
Other Regulatory Assets (Liabilities) [Member]
Other Regulatory Assets (Liabilities) [Member]
Removal Costs [Member]
Removal Costs [Member]
Deferred Income Tax Charge [Member]
Deferred Income Tax Charge [Member]
Asset Retirement Obligation Costs [Member]
Asset Retirement Obligation Costs [Member]
Regulatory Assets and Liabilities [Line Items]
Regulatory Assets [Line Items]
Regulatory Assets, Current
Regulatory Liability, Current
Operating Lease, Weighted Average Remaining Lease Term
Operating Lease, Weighted Average Remaining Lease Term
Finance Lease, Weighted Average Remaining Lease Term
Finance Lease, Weighted Average Remaining Lease Term
Operating Lease, Weighted Average Discount Rate, Percent
Operating Lease, Weighted Average Discount Rate, Percent
Finance Lease, Weighted Average Discount Rate, Percent
Finance Lease, Weighted Average Discount Rate, Percent
Operating Lease, Cost
Operating Lease, Cost
Finance Lease, Right-of-Use Asset, Amortization
Finance Lease, Right-of-Use Asset, Amortization
Finance Lease, Interest Expense
Finance Lease, Interest Expense
FinanceLeaseCost
FinanceLeaseCost
Total Finance Lease Cost
Variable Lease, Cost
Variable Lease, Cost