Stockholders' Equity - Reclassifications from AOCI (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Non-interest income (expense)	$ 252	$ 275	$ 559	$ 474
Income tax provision (benefit)	54	297	356	500
Net income	597	1,431	1,877	2,391
Interest Income (Loss)	7,546	7,113	15,034	14,299
Income (Loss) from continuing operations before income taxes	651	1,728	2,233	2,891
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income	(243)	(240)	(420)	(443)
Securities Available for Sale | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Non-interest income (expense)	0	0	0	0
Income tax provision (benefit)	0	0	0	0
Net income	0	0	0	0
Hedging relationships: | Interest rate contracts: | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest Income (Loss)	(313)	(297)	(622)	(559)
Hedging relationships: | Foreign exchange and other contracts | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Non-interest income (expense)	(19)	(22)	55	(30)
Income tax provision (benefit)	(78)	(76)	(135)	(141)
Net income	(243)	(240)	(420)	(443)
Interest Income (Loss)	3	3	5	6
Interest expense	8	0	7	(1)
Income (Loss) from continuing operations before income taxes	(321)	(316)	(555)	(584)
Other: | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax provision (benefit)	0	0	0	0
Net income	0	0	0	0
Income (Loss) from continuing operations before income taxes	$ 0	$ 0	$ 0	$ 0