Parent Company Financial Statements - Condensed Statements of Income - Parent Company Only (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income
Dividends from consolidated nonbank subsidiaries		$ 1,300	$ 2,000
Securities gains, net	[1]	62	40	$ (54)
Total interest income		5,572	6,254	5,183
Expenses
Interest		790	1,457	1,043
Other		221	232	210
Income Before Income Taxes and Change in Undistributed Earnings of Subsidiaries		1,797	3,202	2,765
Applicable income tax expense		370	690	572
Net Income		1,427	2,512	2,193
Other Comprehensive Income		1,409	1,304	(183)
Parent Company
Income
Dividends from consolidated nonbank subsidiaries		1,285	2,155	1,890
Securities gains, net		1	2	0
Interest on loans to subsidiaries		17	24	24
Total interest income		1,303	2,181	1,914
Expenses
Interest		266	267	211
Other		26	65	34
Total expenses		292	332	245
Income Before Income Taxes and Change in Undistributed Earnings of Subsidiaries		1,011	1,849	1,669
Applicable income tax expense		(65)	(69)	(50)
Income Before Change in Undistributed Earnings of Subsidiaries		1,076	1,918	1,719
Equity in undistributed earnings		351	594	474
Net Income		1,427	2,512	2,193
Other Comprehensive Income		0	0	0
Comprehensive income attributable to Bancorp		$ 1,427	$ 2,512	$ 2,193

[1] During the first quarter of 2020, certain noninterest income and noninterest expense line items were reclassified to better align disclosures to business activities. These reclassifications were retrospectively applied to all prior periods presented. Total noninterest income and noninterest expense did not change as a result of these reclassifications.