Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022		Dec. 31, 2021		Dec. 31, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive loss at beginning of period	$ 8,444
Total income tax expense	37		$ 33		$ 45
Accumulated other comprehensive loss at end of period	9,230		8,444
Gains and Losses on Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive loss at beginning of period	(21)		(23)
Amortization of net actuarial income (loss)			(1)
Net current period other comprehensive income (loss)	1		2
Accumulated other comprehensive loss at end of period	(20)		(21)		(23)
Other Comprehensive Income (Loss) before reclassifications	0
Gains and Losses on Cash Flow Hedges | Interest Rate Swap
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amortization of net actuarial income (loss)	(1)	[1]	(1)	[2]
Defined Benefit Pension and Postretirement Items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive loss at beginning of period	(1)		(1)
Amortization of net actuarial income (loss)			0
Net current period other comprehensive income (loss)	(1)		0
Accumulated other comprehensive loss at end of period	(2)		(1)		(1)
Other Comprehensive Income (Loss) before reclassifications	(1)
Defined Benefit Pension and Postretirement Items | Interest Rate Swap
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amortization of net actuarial income (loss)	0		0
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive loss at beginning of period	(22)		(24)
Amortization of net actuarial income (loss)			(1)
Net current period other comprehensive income (loss)	0		2
Accumulated other comprehensive loss at end of period	(22)		(22)		$ (24)
Other Comprehensive Income (Loss) before reclassifications	(1)
Total | Interest Rate Swap
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amortization of net actuarial income (loss)	$ (1)		$ (1)

[1] Included in interest charges.

[2] Included in interest charges.