Stockholders' Equity - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI beginning balance	$ 3,494
Other comprehensive income (loss), net of tax	(3,120)	$ 2,346	$ 1,531
AOCI ending balance	374	3,494
Effects from transfer of securities held to maturity to available for sale			888
Accounting Standards Update 2017-12
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Amounts reclassified from AOCI into earnings			360
Securities available for sale | Available-for-sale securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI beginning balance	2,186	935	(439)
Other comprehensive income (loss) before reclassifications	(1,887)	1,278	670
Amounts reclassified from AOCI into earnings	(2)	(19)
Other comprehensive income (loss), net of tax	(1,889)	1,259	650
AOCI ending balance	297	2,186	935
Effects from transfer of securities held to maturity to available for sale			724
Securities available for sale | Securities Held to Maturity
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI beginning balance	0	0	(190)
Other comprehensive income (loss) before reclassifications	0	0	0
Amounts reclassified from AOCI into earnings	0	0	26
Other comprehensive income (loss), net of tax	0	0	26
AOCI ending balance	0	0	0
Effects from transfer of securities held to maturity to available for sale			164
Securities available for sale | Accounting Standards Update 2017-12 | Available-for-sale securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Amounts reclassified from AOCI into earnings			(20)
Hedging Relationships
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI beginning balance	1,362	354	(418)
Other comprehensive income (loss) before reclassifications	(396)	1,401	414
Amounts reclassified from AOCI into earnings	(848)	(393)
Other comprehensive income (loss), net of tax	(1,244)	1,008	772
AOCI ending balance	118	1,362	354
Effects from transfer of securities held to maturity to available for sale			0
Hedging Relationships | Accounting Standards Update 2017-12
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Amounts reclassified from AOCI into earnings			358
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI beginning balance	(31)	(107)	(177)
Other comprehensive income (loss) before reclassifications	10	76	70
Amounts reclassified from AOCI into earnings	0	0
Other comprehensive income (loss), net of tax	10	76	70
AOCI ending balance	(21)	(31)	(107)
Effects from transfer of securities held to maturity to available for sale			0
Foreign Currency Translation Adjustments | Accounting Standards Update 2017-12
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Amounts reclassified from AOCI into earnings			0
Other
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI beginning balance	(23)	(26)	(39)
Other comprehensive income (loss) before reclassifications	7	5	17
Amounts reclassified from AOCI into earnings	(4)	(2)
Other comprehensive income (loss), net of tax	3	3	13
AOCI ending balance	(20)	(23)	(26)
Effects from transfer of securities held to maturity to available for sale			0
Other | Accounting Standards Update 2017-12
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Amounts reclassified from AOCI into earnings			(4)
Total
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI beginning balance	3,494	1,156	(1,263)
Other comprehensive income (loss) before reclassifications	(2,266)	2,760	1,171
Amounts reclassified from AOCI into earnings	(854)	(414)
Other comprehensive income (loss), net of tax	(3,120)	2,346	1,531
AOCI ending balance	374	3,494	1,156
Effects from transfer of securities held to maturity to available for sale			888
Net investment hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Other comprehensive gain (loss)	$ 22	(65)	$ (49)
Other comprehensive income before reclassifications | Securities available for sale | Available-for-sale securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Other comprehensive income (loss) before reclassifications		(8)
Other comprehensive income before reclassifications | Hedging Relationships
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Other comprehensive income (loss) before reclassifications		0
Other comprehensive income before reclassifications | Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Other comprehensive income (loss) before reclassifications		0
Other comprehensive income before reclassifications | Other
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Other comprehensive income (loss) before reclassifications		0
Other comprehensive income before reclassifications | Total
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Other comprehensive income (loss) before reclassifications		$ (8)