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 income (loss) at beginning of period	$ 15,612
Total income tax benefit	(135)		$ (70)		$ (6)
Accumulated other comprehensive income (loss) at end of period	16,675		15,612
Gains and Losses on Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss) at beginning of period	(75)		(85)
Other comprehensive loss before reclassifications, net of tax	16		4
Amortization of net actuarial loss	0		0
Net current period other comprehensive income (loss)	21		10
Accumulated other comprehensive income (loss) at end of period	(54)		(75)		(85)
Gains and Losses on Cash Flow Hedges | Interest Rate Swap
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amortization of net actuarial loss	(5)	[1]	(6)	[2]
Defined Benefit Pension and Postretirement Items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss) at beginning of period	(48)		(56)
Other comprehensive loss before reclassifications, net of tax	5		0
Amortization of net actuarial loss	(4)	[3]	(8)	[4]
Net current period other comprehensive income (loss)	9		8
Accumulated other comprehensive income (loss) at end of period	(39)		(48)		(56)
Defined Benefit Pension and Postretirement Items | Interest Rate Swap
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amortization of net actuarial loss	0		0
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss) at beginning of period	(123)		(141)
Other comprehensive loss before reclassifications, net of tax	21		4
Amortization of net actuarial loss	(4)		(8)
Net current period other comprehensive income (loss)	30		18
Accumulated other comprehensive income (loss) at end of period	(93)		(123)		$ (141)
Total | Interest Rate Swap
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amortization of net actuarial loss	$ (5)		$ (6)

[1] Included in interest charges.

[2] Included in interest charges.

[3] Included in the computation of net periodic pension and postretirement benefit costs. See Note 11 for further information.

[4] Included in the computation of net periodic pension and postretirement benefit costs. See Note 11 for further information.