Parent Company Condensed Financial Information (Condensed Statement of Comprehensive Income (loss)) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net financing revenue and other interest income		$ 6,201	$ 6,850	$ 6,167
Total other revenue		2,013	1,578	2,039
Total net revenue		8,214	8,428	8,206
Provision for credit losses		1,968	1,399	241
Total noninterest expense		5,163	4,687	4,110
Income (loss) from continuing operations before income tax expense		1,083	2,342	3,855
Income tax benefit from continuing operations		61	627	790
Net income from continuing operations	[1]	1,022	1,715	3,065
Loss from discontinued operations, net of tax	[1]	(2)	(1)	(5)
Net income		1,020	1,714	3,060
Other comprehensive income (loss)		243	(3,901)	(789)
Comprehensive income (loss)		1,263	(2,187)	2,271
Parent company
Net financing revenue and other interest income		(945)	(1,000)	(1,070)
Dividends from bank subsidiaries		1,350	3,150	3,450
Dividends from nonbank subsidiaries		250	1	27
Total other revenue		169	103	243
Total net revenue		824	2,254	2,650
Provision for credit losses		(14)	(32)	(106)
Total noninterest expense		466	665	650
Income (loss) from continuing operations before income tax expense		372	1,621	2,106
Income tax benefit from continuing operations		(408)	(253)	(412)
Net income from continuing operations		780	1,874	2,518
Loss from discontinued operations, net of tax		(2)	(1)	(5)
Equity in undistributed earnings of subsidiaries		242	(159)	547
Net income		1,020	1,714	3,060
Other comprehensive income (loss)		243	(3,901)	(789)
Comprehensive income (loss)		$ 1,263	$ (2,187)	$ 2,271

[1] Figures in the table may not recalculate exactly due to rounding. Earnings per share is calculated based on unrounded numbers.