Reclassifications Out of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other net periodic benefit credits	$ 3	$ 4
Provision (benefit) for income taxes	109	(517)
Net income	417	1,304
Reclassification out of Accumulated Other Comprehensive Income (Loss) | Total reclassifications of (income) expense, net of tax
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income	4	4
Reclassification out of Accumulated Other Comprehensive Income (Loss) | Amortization of prior service credit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other net periodic benefit credits	6	6
Reclassification out of Accumulated Other Comprehensive Income (Loss) | Amortization of actuarial loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other net periodic benefit credits	0	(1)
Reclassification out of Accumulated Other Comprehensive Income (Loss) | Net settlement loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other net periodic benefit credits	(1)	0
Reclassification out of Accumulated Other Comprehensive Income (Loss) | Income taxes
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Provision (benefit) for income taxes	$ (1)	$ (1)