Stockholders' Equity - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI beginning balance	$ (8,268)
Other comprehensive income (loss) before reclassifications	(1,443)	$ 1,173
Amounts reclassified from AOCI into earnings	177	203
Other comprehensive income (loss), net of tax	(1,266)	1,376
AOCI ending balance	(9,534)
Securities Available for Sale
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI beginning balance	(6,769)	(7,676)
Other comprehensive income (loss) before reclassifications	(844)	962
Amounts reclassified from AOCI into earnings	0	0
Other comprehensive income (loss), net of tax	(844)	962
AOCI ending balance	(7,613)	(6,714)
Hedging relationships:
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI beginning balance	(1,493)	(2,182)
Other comprehensive income (loss) before reclassifications	(587)	198
Amounts reclassified from AOCI into earnings	177	203
Other comprehensive income (loss), net of tax	(410)	401
AOCI ending balance	(1,903)	(1,781)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI beginning balance	26	(20)
Other comprehensive income (loss) before reclassifications	(13)	13
Amounts reclassified from AOCI into earnings	0	0
Other comprehensive income (loss), net of tax	(13)	13
AOCI ending balance	13	(7)
Other:
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI beginning balance	(32)	(38)
Other comprehensive income (loss) before reclassifications	1	0
Amounts reclassified from AOCI into earnings	0	0
Other comprehensive income (loss), net of tax	1	0
AOCI ending balance	(31)	(38)
Total
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI beginning balance	(8,268)	(9,916)
AOCI ending balance	(9,534)	(8,540)
Net investment hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Other comprehensive gain (loss)	$ 49	$ (38)