Commitments (Other Commitments) (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Other Commitments [Line Items]
Commitments	$ 252,426	$ 250,854
Liability Related To Investments In Low Income Housing Tax Credits	2,000	2,000
Commitments to extend credit
Other Commitments [Line Items]
Commitments	238,756	237,238
Commitments to extend credit | Commercial
Other Commitments [Line Items]
Commitments	177,074	176,248
Commitments to extend credit | Home equity lines of credit
Other Commitments [Line Items]
Commitments	19,976	19,410
Commitments to extend credit | Credit card
Other Commitments [Line Items]
Commitments	32,668	32,499
Commitments to extend credit | Other
Other Commitments [Line Items]
Commitments	9,038	9,081
Standby letters of credit
Other Commitments [Line Items]
Commitments	9,507	9,303
Standby letters of credit | Remarketing Programs
Other Commitments [Line Items]
Commitments	3,600	3,300
Standby bond purchase agreements
Other Commitments [Line Items]
Commitments	1,254	1,268
Other commitments
Other Commitments [Line Items]
Commitments	$ 2,909	$ 3,045