Accumulated Other Comprehensive Income - Components in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax expense (benefit)	$ 1	$ 12	$ 52
Net income (loss)	2,006	172	155
Interest expense	479	$ 302	$ 97
Reclassifications, net of tax	3
Past service liability
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications, before tax	0
Actuarial losses
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications, before tax	(2)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications, before tax	(2)
Reclassification of certain income tax effects	1
Reclassifications, net of tax	(1)
Reclassification from AOCI | Unrealized gains on available-for-sale securities:
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net gain on securities	0
Income tax expense (benefit)
Net income (loss)	0
Reclassification from AOCI | Unrealized gains on cash flow hedges:
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax expense (benefit)	(2)
Net income (loss)	4
Interest expense	$ 6