Interest Rate Derivative (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Other Derivative Instruments
Interest Rate Derivatives [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		$ 0	$ 0	$ 0	$ 0
Pre-tax gains (losses) reclassified into income during the period from regulatory assets and (liabilities)		10	(2)	31	(3)
Pre-tax gains (losses) recognized during the period in income		(2)	11	(8)	12
Designated as Hedging Instrument [Member] | Cash Flow Hedges
Interest Rate Derivatives [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		1		1
Pre-tax gains (losses) reclassified into income during the period from regulatory assets and (liabilities)		0		0
Pre-tax gains (losses) recognized during the period in income		0		0
Interest Rate Derivatives
Interest Rate Derivatives [Abstract]
Amount or interest rate derivatives expected to be reclassified		1		1
Derivative Liability, Notional Amount		0		0
Commodity Trading Contract | Other Derivative Instruments
Interest Rate Derivatives [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		0	0	0	0
Pre-tax gains (losses) reclassified into income during the period from regulatory assets and (liabilities)		0	0	0	0
Pre-tax gains (losses) recognized during the period in income	[1]	(2)	11	(3)	17
Electric Commodity | Other Derivative Instruments
Interest Rate Derivatives [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		0	0	0	0
Pre-tax gains (losses) reclassified into income during the period from regulatory assets and (liabilities)	[2]	(10)	2	31	(5)
Pre-tax gains (losses) recognized during the period in income		0	$ 0	0	0
Natural Gas Commodity | Other Derivative Instruments
Interest Rate Derivatives [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net				0	0
Pre-tax gains (losses) reclassified into income during the period from regulatory assets and (liabilities)				0	(2)	[3]
Pre-tax gains (losses) recognized during the period in income	[3],[4]			(5)	$ (5)
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedges
Interest Rate Derivatives [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	[5]	1		1
Pre-tax gains (losses) reclassified into income during the period from regulatory assets and (liabilities)		0		0
Pre-tax gains (losses) recognized during the period in income		$ 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.