Parent Company Financial Statements - Statement of Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Total revenue	$ 11,756	$ 12,131	$ 11,266
Other	1,262	1,176	929
Total expenses	9,034	9,015	8,269
Income tax expense	470	508	839
Equity in undistributed income of consolidated subsidiaries and unconsolidated entities:
Net income	2,242	2,593	2,156
Parent Company
Condensed Financial Statements, Captions [Line Items]
Cash dividends from consolidated banking subsidiary	3,300	785	2,224
Cash dividends from consolidated non-banking subsidiaries and unconsolidated entities	285	41	12
Other, net	149	58	127
Total revenue	3,734	884	2,363
Interest expense	415	381	297
Other	108	162	94
Total expenses	523	543	391
Income tax expense	(91)	(127)	(86)
Income before equity in undistributed income of consolidated subsidiaries and unconsolidated entities	3,302	468	2,058
Equity in undistributed income of consolidated subsidiaries and unconsolidated entities:
Consolidated banking subsidiary	(1,070)	1,944	(1)
Consolidated non-banking subsidiaries and unconsolidated entities	10	181	99
Net income	$ 2,242	$ 2,593	$ 2,156