Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2023		Sep. 30, 2022	Sep. 30, 2023		Sep. 30, 2022
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive (loss) income at beginning of period				$ 7,836
Accumulated other comprehensive (loss) income at end of period	$ 8,152			8,152
Income Tax Expense (Benefit)	13		$ 12	(79)		$ (70)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0		0	0		0
Gains and Losses on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive (loss) income at beginning of period	(13)		(17)	(16)		(17)
Accumulated other comprehensive (loss) income at end of period	(13)		(17)	(13)		(17)
Other Comprehensive Income (Loss), Net of Tax	0			3		0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax				3
Gains and Losses on Cash Flow Hedges | Interest Rate Swap [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0		0	0		0
Defined Benefit Pension and Postretirement Items
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive (loss) income at beginning of period	(2)		(3)	(2)		(3)
Accumulated other comprehensive (loss) income at end of period	(1)		(3)	(1)		(3)
Other Comprehensive Income (Loss), Net of Tax	1			1		0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0			0
Defined Benefit Pension and Postretirement Items | Interest Rate Swap [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	1	[1]	0	1	[1]	0
Total
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive (loss) income at beginning of period	(15)		(20)	(18)		(20)
Accumulated other comprehensive (loss) income at end of period	(14)		(20)	(14)		(20)
Other Comprehensive Income (Loss), Net of Tax	1		0	4		0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0			3
Total | Interest Rate Swap [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	$ 1	[1]	$ 0	$ 1	[1]	$ 0

[1] Included in interest charges.