Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024		Dec. 31, 2023		Dec. 31, 2022
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss) at beginning of period	$ 17,616
Total income tax benefit	(402)		$ (146)		$ (135)
Accumulated other comprehensive income (loss) at end of period	19,522		17,616
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	(53)		(54)
Other comprehensive loss before reclassifications, net of tax	22		(2)
Amortization of net actuarial loss	0		0
Net current period other comprehensive income (loss)	24		1
Accumulated other comprehensive income (loss) at end of period	(29)		(53)		(54)
Gains and Losses on Cash Flow Hedges | Interest Rate Swap
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amortization of net actuarial loss	(2)	[1]	(3)	[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	(41)		(39)
Other comprehensive loss before reclassifications, net of tax	(3)		(4)
Amortization of net actuarial loss	(5)	[3]	(2)	[4]
Net current period other comprehensive income (loss)	2		(2)
Accumulated other comprehensive income (loss) at end of period	(39)		(41)		(39)
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	(94)		(93)
Other comprehensive loss before reclassifications, net of tax	19		(6)
Amortization of net actuarial loss	(5)		(2)
Net current period other comprehensive income (loss)	26		(1)
Accumulated other comprehensive income (loss) at end of period	(68)		(94)		$ (93)
Total | Interest Rate Swap
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amortization of net actuarial loss	$ (2)		$ (3)

[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.