Stockholders' Equity - Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Before Tax
Net unrealized gains (losses) on securities available for sale	$ (2,780)	$ (3,882)	$ (2,684)	$ (11,181)
Net unrealized gains (losses) on hedging relationships	(342)	(1,065)	(372)	(3,292)
Foreign currency translation adjustments	(2)	33	8	47
Other	0	(1)	0	(1)
Other comprehensive income (loss), before tax	(3,124)	(4,915)	(3,048)	(14,427)
Provision (Benefit)
Net unrealized gains (losses) on securities available for sale	(672)	(947)	(650)	(2,705)
Net unrealized gains (losses) on hedging relationships	(83)	(261)	(90)	(796)
Foreign currency translation adjustments	37	81	0	152
Other	0	0	0	0
Other comprehensive income (loss), provision (benefit)	(718)	(1,127)	(740)	(3,349)
After Tax
Net unrealized gains (losses) on securities available for sale	(2,108)	(2,935)	(2,034)	(8,476)
Net unrealized gains (losses) on hedging relationships	(259)	(804)	(282)	(2,496)
Foreign currency translation adjustments	(39)	(48)	8	(105)
Other	0	(1)	0	(1)
Other comprehensive loss, net of tax	$ (2,406)	$ (3,788)	$ (2,308)	$ (11,078)