Commitments (Other Commitments) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Other Commitments [Line Items]
Commitments	$ 250,854	$ 220,368
Liability related to investments in low income housing tax credits	2,000	1,100
Commitments to extend credit
Other Commitments [Line Items]
Commitments	237,238	207,821
Commitments to extend credit | Total commercial lending
Other Commitments [Line Items]
Commitments	176,248	153,089
Commitments to extend credit | Home equity lines of credit
Other Commitments [Line Items]
Commitments	19,410	16,626
Commitments to extend credit | Credit card
Other Commitments [Line Items]
Commitments	32,499	31,019
Commitments to extend credit | Other
Other Commitments [Line Items]
Commitments	9,081	7,087
Standby letters of credit
Other Commitments [Line Items]
Commitments	9,303	9,053
Standby letters of credit | Remarketing Programs
Other Commitments [Line Items]
Commitments	3,300	3,800
Standby bond purchase agreements
Other Commitments [Line Items]
Commitments	1,268	1,448
Other commitments
Other Commitments [Line Items]
Commitments	$ 3,045	$ 2,046