Parent Company Financial Statements (Condensed Statements of Income - Parent Company Only) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Dividends from subsidiaries:
Consolidated nonbank subsidiaries	$ 2,000	$ 1,900
Securities gains, net	40	(54)	$ 2
Total interest income	6,254	5,183	4,489
Expenses
Interest	1,457	1,043	691
Other	239	214	184
Income Before Income Taxes and Change in Undistributed Earnings of Subsidiaries	3,202	2,765	2,979
Applicable income tax benefit	690	572	799
Net Income (Loss) Attributable to Parent	2,512	2,193	2,180
Other Comprehensive Income (loss)	1,304	(183)	14
Comprehensive income attributable to Bancorp	3,816	2,010	2,194
Parent Company Only
Dividends from subsidiaries:
Consolidated nonbank subsidiaries	2,155	1,890	2,343
Securities gains, net	2	0	0
Interest on loans to subsidiaries	24	24	21
Total interest income	2,181	1,914	2,364
Expenses
Interest	267	211	176
Other	65	34	42
Total expenses	332	245	218
Income Before Income Taxes and Change in Undistributed Earnings of Subsidiaries	1,849	1,669	2,146
Applicable income tax benefit	(69)	(50)	(68)
Income (Loss) Before Change in Undistributed Earnings of Subsidiaries	1,918	1,719	2,214
Change in undistributed earnings (loss)	594	474	(34)
Net Income (Loss) Attributable to Parent	2,512	2,193	2,180
Other Comprehensive Income (loss)	0	0	0
Comprehensive income attributable to Bancorp	$ 2,512	$ 2,193	$ 2,180