Accumulated Other Comprehensive Income (Loss), Net of Tax (Tables)

6 Months Ended

Jun. 30, 2023

Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]

Schedule of Changes in Accumulated Other Comprehensive Income by Component

	Three Months Ended June 30, 2023
Accumulated Other Comprehensive Income (Loss)	Cash Flow Hedges		Pension and OPEB Plans		Available-for-Sale Securities		Total
	Millions
Balance as of March 31, 2023	$	(4)	$	(423)	$	(95)	$	(522)
Other Comprehensive Income (Loss) before Reclassifications	12		—		(12)		—
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	(1)		4		4		7
Net Current Period Other Comprehensive Income (Loss)	11		4		(8)		7
Balance as of June 30, 2023	$	7	$	(419)	$	(103)	$	(515)
	Three Months Ended June 30, 2022
Accumulated Other Comprehensive Income (Loss)	Cash Flow Hedges		Pension and OPEB Plans		Available-for-Sale Securities		Total
	Millions
Balance as of March 31, 2022	$	(5)	$	(355)	$	(50)	$	(410)
Other Comprehensive Income (Loss) before Reclassifications	—		—		(53)		(53)
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	—		1		7		8
Net Current Period Other Comprehensive Income (Loss)	—		1		(46)		(45)
Balance as of June 30, 2022	$	(5)	$	(354)	$	(96)	$	(455)
	Six Months Ended June 30, 2023
Accumulated Other Comprehensive Income (Loss)	Cash Flow Hedges		Pension and OPEB Plans		Available-for-Sale Securities		Total
	Millions
Balance as of December 31, 2022	$	(3)	$	(426)	$	(121)	$	(550)
Other Comprehensive Income (Loss) before Reclassifications	10		—		8		18
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	—		7		10		17
Net Current Period Other Comprehensive Income (Loss)	10		7		18		35
Balance as of June 30, 2023	$	7	$	(419)	$	(103)	$	(515)
	Six Months Ended June 30, 2022
Accumulated Other Comprehensive Income (Loss)	Cash Flow Hedges		Pension and OPEB Plans		Available-for-Sale Securities		Total
	Millions
Balance as of December 31, 2021	$	(6)	$	(355)	$	11	$	(350)
Other Comprehensive Income (Loss) before Reclassifications	—		—		(118)		(118)
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	1		1		11		13
Net Current Period Other Comprehensive Income (Loss)	1		1		(107)		(105)
Balance as of June 30, 2022	$	(5)	$	(354)	$	(96)	$	(455)

Reclassifications out of Accumulated Other Comprehensive Income

		Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) to Income Statement
		Three Months Ended						Six Months Ended
		June 30, 2023						June 30, 2023
Description of Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	Location of Pre-Tax Amount In Statement of Operations	Pre-Tax Amount		Tax (Expense) Benefit		After-Tax Amount		Pre-Tax Amount		Tax (Expense) Benefit		After-Tax Amount
		Millions
Cash Flow Hedges
Interest Rate Swaps	Interest Expense	$	1	$	—	$	1	$	—	$	—	$	—
Total Cash Flow Hedges		1		—		1		—		—		—
Pension and OPEB Plans
Amortization of Prior Service (Cost) Credit	Non-Operating Pension and OPEB Credits (Costs)	2		(1)		1		4		(1)		3
Amortization of Actuarial Loss	Non-Operating Pension and OPEB Credits (Costs)	(7)		2		(5)		(14)		4		(10)
Total Pension and OPEB Plans		(5)		1		(4)		(10)		3		(7)
Available-for-Sale Debt Securities
Realized Gains (Losses)	Net Gains (Losses) on Trust Investments	(7)		3		(4)		(17)		7		(10)
Total Available-for-Sale Debt Securities		(7)		3		(4)		(17)		7		(10)
Total		$	(11)	$	4	$	(7)	$	(27)	$	10	$	(17)

		Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) to Income Statement
		Three Months Ended						Six Months Ended
		June 30, 2022						June 30, 2022
Description of Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	Location of Pre-Tax Amount In Statement of Operations	Pre-Tax Amount		Tax (Expense) Benefit		After-Tax Amount		Pre-Tax Amount		Tax (Expense) Benefit		After-Tax Amount
		Millions
Cash Flow Hedges
Interest Rate Swaps	Interest Expense	$	(1)	$	1	$	—	$	(2)	$	1	$	(1)
Total Cash Flow Hedges		(1)		1		—		(2)		1		(1)
Pension and OPEB Plans
Amortization of Prior Service (Cost) Credit	Non-Operating Pension and OPEB Credits (Costs)	5		(2)		3		10		(3)		7
Amortization of Actuarial Loss	Non-Operating Pension and OPEB Credits (Costs)	(6)		2		(4)		(11)		3		(8)
Total Pension and OPEB Plans		(1)		—		(1)		(1)		—		(1)
Available-for-Sale Debt Securities
Realized Gains (Losses)	Net Gains (Losses) on Trust Investments	(12)		5		(7)		(18)		7		(11)
Total Available-for-Sale Debt Securities		(12)		5		(7)		(18)		7		(11)
Total		$	(14)	$	6	$	(8)	$	(21)	$	8	$	(13)