Parent Company Only Condensed Financial Information - Condensed Statements of Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Condensed Income Statements, Captions [Line Items]
Interest income	$ 3,289	$ 2,242	$ 2,310
Interest expense	(110)	(85)	(213)
Gains on equity warrant assets, net	560	237	138
Gains on investment securities, net	761	421	135
Income tax expense	(651)	(448)	(425)
Preferred stock dividends	(63)	(17)	0
Net income available to common stockholders	1,770	1,191	1,137
Parent Company
Condensed Income Statements, Captions [Line Items]
Interest income	3	3	5
Interest expense	(48)	(22)	(32)
Dividend income from bank subsidiary	0	50	733
Gains on equity warrant assets, net	554	227	138
Gains on investment securities, net	197	158	45
Fund management fees and other noninterest income	68	62	22
General and administrative expenses	(298)	(121)	(95)
Income tax expense	(212)	(146)	(40)
Income before net income of subsidiaries	264	211	776
Net income before preferred stock dividend	1,833	1,208	1,137
Preferred stock dividends	(63)	(17)	0
Net income available to common stockholders	1,770	1,191	1,137
Parent Company | Bank Subsidiary
Condensed Income Statements, Captions [Line Items]
Income before net income of subsidiaries	1,294	826	1,037
Equity in undistributed net income of subsidiaries	1,294	776	304
Parent Company | Nonbank Subsidiaries
Condensed Income Statements, Captions [Line Items]
Income before net income of subsidiaries	275	221	57
Equity in undistributed net income of subsidiaries	$ 275	$ 221	$ 57