Stockholders' Equity - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI beginning balance	$ (9,916)
Other comprehensive income (loss) before reclassifications	666	$ (10,400)	$ (2,266)
Amounts reclassified from AOCI into earnings	982	110	(854)
Other comprehensive income (loss), net of tax	1,648	(10,290)	(3,120)
AOCI ending balance	(8,268)	(9,916)
Securities Available for Sale | Securities Available for Sale
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI beginning balance	(7,676)	297	2,186
Other comprehensive income (loss) before reclassifications	881	(7,980)	(1,887)
Amounts reclassified from AOCI into earnings	26	7	(2)
Other comprehensive income (loss), net of tax	907	(7,973)	(1,889)
AOCI ending balance	(6,769)	(7,676)	297
Hedging relationships:
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI beginning balance	(2,182)	118	1,362
Other comprehensive income (loss) before reclassifications	(268)	(2,404)	(396)
Amounts reclassified from AOCI into earnings	957	104	(848)
Other comprehensive income (loss), net of tax	689	(2,300)	(1,244)
AOCI ending balance	(1,493)	(2,182)	118
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI beginning balance	(20)	(21)	(31)
Other comprehensive income (loss) before reclassifications	46	1	10
Amounts reclassified from AOCI into earnings	0	0	0
Other comprehensive income (loss), net of tax	46	1	10
AOCI ending balance	26	(20)	(21)
Other:
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI beginning balance	(38)	(20)	(23)
Other comprehensive income (loss) before reclassifications	7	(17)	7
Amounts reclassified from AOCI into earnings	(1)	(1)	(4)
Other comprehensive income (loss), net of tax	6	(18)	3
AOCI ending balance	(32)	(38)	(20)
Total
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI beginning balance	(9,916)	374	3,494
AOCI ending balance	(8,268)	(9,916)	374
Net investment hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Other comprehensive gain (loss)	$ (126)	$ 305	$ 22