Stockholders' Equity - Reclassifications from AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income	$ 24,171	$ 22,913	$ 23,340
Interest expense	1,598	3,120	5,173
Non-interest income	824	1,325	718
Income (loss) from continuing operations before income taxes	15,809	3,203	6,874
Income tax provision	3,415	486	1,341
Net income (loss)	12,390	2,714	5,546
Accumulated other comprehensive income	374	3,494
Other comprehensive income (loss), net of tax	(3,120)	2,346	1,531
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income (loss)	854	414	(360)
Securities available for sale | Securities Held to Maturity
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Accumulated other comprehensive income	0	0	0	$ (190)
Other comprehensive income (loss) before reclassifications	0	0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0	26
Other comprehensive income (loss), net of tax	0	0	26
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	2	25	26
Income tax provision	0	6	6
Net income (loss)	2	19	20
Securities available for sale | Reclassification out of Accumulated Other Comprehensive Income [Member] | Securities Held to Maturity
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income	0	0	(35)
Income tax provision	0	0	(9)
Net income (loss)	0	0	(26)
Hedging Relationships
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Accumulated other comprehensive income	118	1,362	354	(418)
Other comprehensive income (loss) before reclassifications	(396)	1,401	414
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(848)	(393)
Other comprehensive income (loss), net of tax	(1,244)	1,008	772
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	957	566	(171)
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	1	10	44
Interest expense	(3)	(3)	(2)
Non-interest income	163	(57)	(341)
Income (loss) from continuing operations before income taxes	1,118	516	(470)
Income tax provision	270	123	(112)
Net income (loss)	848	393	(358)
Foreign Currency Translation Adjustments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Accumulated other comprehensive income	(21)	(31)	(107)	(177)
Other comprehensive income (loss) before reclassifications	10	76	70
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0
Other comprehensive income (loss), net of tax	10	76	70
Other
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Accumulated other comprehensive income	(20)	(23)	(26)	(39)
Other comprehensive income (loss) before reclassifications	7	5	17
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(4)	(2)
Other comprehensive income (loss), net of tax	3	3	13
Other | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income (loss) from continuing operations before income taxes	5	2	5
Income tax provision	1	0	1
Net income (loss)	4	2	4
Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Accumulated other comprehensive income	374	3,494	1,156	$ (1,263)
Other comprehensive income (loss) before reclassifications	(2,266)	2,760	1,171
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(854)	(414)
Other comprehensive income (loss), net of tax	$ (3,120)	$ 2,346	$ 1,531