Qualifying Cash Flow Hedges (Details) - USD ($)		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Financial Impact of Qualifying Cash Flow Hedges on Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax		$ (5,000,000)	$ (6,000,000)	$ (5,000,000)
Impact of Derivative Activity
Fair Value Hedges, Net		0	0	0
Not Designated as Hedging Instrument
Impact of Derivative Activity
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax		0	0	0
Derivative Instruments Gain (Loss) Reclassified To Regulatory Assets And Liabilities Net		(26,000,000)	28,000,000	(18,000,000)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		0	0	0
Pre-tax gains (losses) reclassified into income during the period from regulatory assets and (liabilities)		13,000,000	18,000,000	(7,000,000)
Derivative, Gain (Loss) on Derivative, Net		(2,000,000)	41,000,000	(14,000,000)
Not Designated as Hedging Instrument | Commodity Trading Contract
Impact of Derivative Activity
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		0	0	0
Pre-tax gains (losses) reclassified into income during the period from regulatory assets and (liabilities)		0	0	0
Derivative, Gain (Loss) on Derivative, Net	[1]	25,000,000	63,000,000	(1,000,000)
Not Designated as Hedging Instrument | Electric Commodity Contract
Impact of Derivative Activity
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax		0	0	0
Derivative Instruments Gain (Loss) Reclassified To Regulatory Assets And Liabilities Net		(10,000,000)	32,000,000	(5,000,000)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		0	0	0
Pre-tax gains (losses) reclassified into income during the period from regulatory assets and (liabilities)	[2]	(3,000,000)	23,000,000	3,000,000
Derivative, Gain (Loss) on Derivative, Net		0	0	0
Not Designated as Hedging Instrument | Natural Gas Commodity Contract
Impact of Derivative Activity
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax		0	0	0
Derivative Instruments Gain (Loss) Reclassified To Regulatory Assets And Liabilities Net		(16,000,000)	(4,000,000)	(13,000,000)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		0	0	0
Pre-tax gains (losses) reclassified into income during the period from regulatory assets and (liabilities)	[3]	10,000,000	5,000,000	(10,000,000)
Derivative, Gain (Loss) on Derivative, Net	[3],[4]	(27,000,000)	(22,000,000)	(13,000,000)
Cash Flow Hedges | Designated as Hedging Instrument
Impact of Derivative Activity
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax		22,000,000	5,000,000	(13,000,000)
Derivative Instruments Gain (Loss) Reclassified To Regulatory Assets And Liabilities Net		0	0	0
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		(7,000,000)	(8,000,000)	(7,000,000)
Pre-tax gains (losses) reclassified into income during the period from regulatory assets and (liabilities)		0	0	0
Derivative, Gain (Loss) on Derivative, Net		0	0	0
Cash Flow Hedges | Designated as Hedging Instrument | Interest Rate Contract
Impact of Derivative Activity
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax		22,000,000	5,000,000	(13,000,000)
Derivative Instruments Gain (Loss) Reclassified To Regulatory Assets And Liabilities Net		0	0	0
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	[5]	(7,000,000)	(8,000,000)	(7,000,000)
Pre-tax gains (losses) reclassified into income during the period from regulatory assets and (liabilities)		0	0	0
Derivative, Gain (Loss) on Derivative, Net		$ 0	$ 0	$ 0

[1] Recorded to electric revenues. Presented amounts do not reflect non-derivative transactions or margin sharing with customers.

[2] Recorded to electric fuel and purchased power. These derivative settlement gains and losses are shared with electric customers through fuel and purchased energy cost-recovery mechanisms and reclassified out of income as regulatory assets or liabilities, as appropriate. FTR settlements are shared with customers and do not have a material impact on net income. Presented amounts reflect changes in fair value between auction and settlement dates, but exclude the original auction fair value.

[3] Recorded to cost of natural gas sold and transported. These losses are subject to cost-recovery mechanisms and reclassified out of income to a regulatory asset, as appropriate.

[4] Relates primarily to option premium amortization.

[5] Recorded to interest charges.