Commitments (Commitments to Extend Credit and Other Commitments) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Other Commitments [Line Items]
Commitments	$ 284,768	$ 277,172
Liability related to investments in low income housing tax credits	2,100	2,200
Commitments to extend credit
Other Commitments [Line Items]
Commitments	268,391	261,728
Commitments to extend credit | Total commercial lending
Other Commitments [Line Items]
Commitments	203,080	198,542
Commitments to extend credit | Home equity
Other Commitments [Line Items]
Commitments	23,970	22,783
Commitments to extend credit | Credit card
Other Commitments [Line Items]
Commitments	33,978	33,066
Commitments to extend credit | Other
Other Commitments [Line Items]
Commitments	7,363	7,337
Standby letters of credit
Other Commitments [Line Items]
Commitments	10,913	10,575
Standby letters of credit | Remarketing Programs
Other Commitments [Line Items]
Commitments	3,900	3,600
Standby bond purchase agreements
Other Commitments [Line Items]
Commitments	1,078	1,208
Other commitments
Other Commitments [Line Items]
Commitments	$ 4,386	$ 3,661