Off-balance Sheet Lending-related Financial Instruments, Guarantees, and Other Commitments - Standby Letters of Credit, Other Financial Guarantees and Other Letters of Credit (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Standby letters of credit and other financial guarantees and other letters of credit [Abstract]
Total lending-related commitments/ contractual amount	$ 1,497,847	$ 1,326,782
Allowance for lending-related commitments	1,974	2,382	$ 2,261	$ 2,409
Total carrying value	4,139	2,817
Standby letters of credit and other financial guarantees
Standby letters of credit and other financial guarantees and other letters of credit [Abstract]
Investment-grade	19,694	19,205
Noninvestment-grade	9,178	8,234
Total lending-related commitments/ contractual amount	28,872	27,439
Allowance for lending-related commitments	110	82
Guarantee liability	369	326
Total carrying value	479	408
Commitments with collateral	16,861	15,296
Other letters of credit
Standby letters of credit and other financial guarantees and other letters of credit [Abstract]
Investment-grade	3,552	3,040
Noninvestment-grade	836	1,094
Total lending-related commitments/ contractual amount	4,388	4,134
Allowance for lending-related commitments	37	6
Guarantee liability	0	0
Total carrying value	37	6
Commitments with collateral	$ 539	$ 795