Parent Company Financial Information - Parent Company Condensed Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Assets
Cash and Due from Banks	$ 5,085	$ 5,029
Interest-bearing deposits with banks	15,210	13,839
AFS securities, Fair Value	153,123	120,788
Other Assets	32,149	30,673
Total assets	541,241	509,228
Liabilities and Equity [Abstract]
Short-term Debt	5,292	6,092
Long-term debt	35,913	39,597
Other Liabilities	14,277	11,550
Liabilities	471,970	438,316
Total shareholders' equity	69,271	70,912	$ 66,558	$ 30,178
Total liabilities and shareholders’ equity	541,241	509,228
Parent Company
Assets
Cash and Due from Banks	598	688
Interest-bearing deposits with banks	9,680	13,434
AFS securities, Fair Value	257	82
Advances to / receivables from subsidiaries:	5,383	6,275
Investment in subsidiaries:	70,426	69,937
Other Assets	419	313
Total assets	86,763	90,729
Liabilities and Equity [Abstract]
Short-term Debt	809	621
Long-term debt	16,504	18,890
Other Liabilities	179	306
Liabilities	17,492	19,817
Total shareholders' equity	69,271	70,912
Total liabilities and shareholders’ equity	86,763	90,729
Parent Company | Banking
Assets
Advances to / receivables from subsidiaries:	2,006	2,541
Investment in subsidiaries:	64,985	65,641
Parent Company | Nonbank
Assets
Advances to / receivables from subsidiaries:	3,377	3,734
Investment in subsidiaries:	$ 5,441	$ 4,296