Stockholders' Equity - Reclassifications from AOCI (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income	$ 6,397	$ 5,822
Interest expense	387	439
Non-interest income	343	122
Income from continuing operations before income taxes	2,945	4,196
Income tax provision	542	869
Net income (loss)	2,403	3,325
Accumulated other comprehensive income (loss)	(4,093)		$ 374
Other comprehensive income (loss), net of tax	(4,467)	(1,711)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income (loss)	86	247
Securities available for sale | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Non-interest income	0	4
Income tax provision	0	1
Net income (loss)	0	3
Hedging Relationships
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Accumulated other comprehensive income (loss)	(1,091)	781	118	$ 1,362
Other comprehensive income (loss) before reclassifications	(1,123)	(338)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(86)	(243)
Other comprehensive income (loss), net of tax	(1,209)	(581)
Hedging Relationships | Interest rate contracts | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income	127	235
Hedging Relationships | Foreign exchange contracts | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income	0	1
Interest expense	(1)	(1)
Non-interest income	(13)	85
Income from continuing operations before income taxes	113	320
Income tax provision	27	77
Net income (loss)	86	243
Foreign Currency Translation Adjustments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Accumulated other comprehensive income (loss)	(26)	(12)	(21)	(31)
Other comprehensive income (loss) before reclassifications	(5)	19
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0
Other comprehensive income (loss), net of tax	(5)	19
Other
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Accumulated other comprehensive income (loss)	(20)	(24)	(20)	(23)
Other comprehensive income (loss) before reclassifications	0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	(1)
Other comprehensive income (loss), net of tax	0	(1)
Other | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations before income taxes	0	1
Income tax provision	0	0
Net income (loss)	0	1
Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Accumulated other comprehensive income (loss)	(4,093)	1,783	$ 374	$ 3,494
Other comprehensive income (loss) before reclassifications	(4,381)	(1,464)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(86)	(247)
Other comprehensive income (loss), net of tax	$ (4,467)	$ (1,711)