Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024	Mar. 31, 2024
Assets:
Available-for-sale debt and other securities:	$ 39,747	$ 39,547
Equity securities	494	341
Derivative Assets	2,190	2,472
Liabilities:
Derivative Liabilities	2,485	2,798
Residential Mortgage
Assets:
Residential mortgage loans	109	108	$ 113
U.S. Treasury and federal agencies securities
Assets:
Available-for-sale debt and other securities:	4,361	4,360
Asset-backed securities and other debt securities
Assets:
Available-for-sale debt and other securities:	3,199	3,729
Other securities
Assets:
Available-for-sale debt and other securities:	824	778
Liabilities:
FHLB, restricted stock holdings	321	276
FRB, restricted stock holdings	501	500
DTCC, restricted stock holdings	2	2
Level 3 | Interest rate contracts
Assets:
Derivative Assets	5		6
Liabilities:
Derivative Liabilities	5		$ 6
Recurring
Assets:
Available-for-sale debt and other securities:	38,923	38,769
Trading debt securities	1,159	1,185
Equity securities	494	341
Residential mortgage loans held for sale	445	574
Derivative Assets	2,190	2,472
Total assets	44,983	45,153
Liabilities:
Derivative Liabilities	2,485	2,798
Short positions	243	316
Total liabilities	2,728	3,114
Recurring | Interest rate contracts
Assets:
Derivative Assets	586	730
Liabilities:
Derivative Liabilities	754	944
Recurring | Foreign exchange contracts
Assets:
Derivative Assets	798	1,167
Liabilities:
Derivative Liabilities	758	1,120
Recurring | Equity contracts
Liabilities:
Derivative Liabilities	173	170
Recurring | Commodity contracts
Assets:
Derivative Assets	806	575
Liabilities:
Derivative Liabilities	800	564
Recurring | Servicing rights
Assets:
Servicing rights	1,663	1,704
Recurring | Residential Mortgage
Assets:
Residential mortgage loans	109	108
Recurring | U.S. Treasury and federal agencies securities
Assets:
Available-for-sale debt and other securities:	4,361	4,360
Trading debt securities	695	626
Liabilities:
Short positions	76	139
Recurring | Obligations of states and political subdivisions securities
Assets:
Trading debt securities	70	120
Recurring | Agency mortgage-backed securities | Residential Mortgage
Assets:
Available-for-sale debt and other securities:	6,601	5,681
Trading debt securities	26	10
Recurring | Agency mortgage-backed securities | Commercial
Assets:
Available-for-sale debt and other securities:	21,056	20,832
Recurring | Non-agency commercial mortgage-backed securities | Commercial
Assets:
Available-for-sale debt and other securities:	3,706	4,167
Recurring | Asset-backed securities and other debt securities
Assets:
Available-for-sale debt and other securities:	3,199	3,729
Trading debt securities	368	429
Liabilities:
Short positions	125	156
Recurring | Equity securities
Liabilities:
Short positions	42	21
Recurring | Level 1
Assets:
Available-for-sale debt and other securities:	4,361	4,360
Trading debt securities	675	591
Equity securities	465	307
Residential mortgage loans held for sale	0	0
Derivative Assets	73	82
Total assets	5,574	5,340
Liabilities:
Derivative Liabilities	167	57
Short positions	118	160
Total liabilities	285	217
Recurring | Level 1 | Interest rate contracts
Assets:
Derivative Assets	1	7
Liabilities:
Derivative Liabilities	2	0
Recurring | Level 1 | Foreign exchange contracts
Assets:
Derivative Assets	0	0
Liabilities:
Derivative Liabilities	0	0
Recurring | Level 1 | Equity contracts
Liabilities:
Derivative Liabilities	0	0
Recurring | Level 1 | Commodity contracts
Assets:
Derivative Assets	72	75
Liabilities:
Derivative Liabilities	165	57
Recurring | Level 1 | Servicing rights
Assets:
Servicing rights	0	0
Recurring | Level 1 | Residential Mortgage
Assets:
Residential mortgage loans	0	0
Recurring | Level 1 | U.S. Treasury and federal agencies securities
Assets:
Available-for-sale debt and other securities:	4,361	4,360
Trading debt securities	675	591
Liabilities:
Short positions	76	139
Recurring | Level 1 | Obligations of states and political subdivisions securities
Assets:
Trading debt securities	0	0
Recurring | Level 1 | Agency mortgage-backed securities | Residential Mortgage
Assets:
Available-for-sale debt and other securities:	0	0
Trading debt securities	0	0
Recurring | Level 1 | Agency mortgage-backed securities | Commercial
Assets:
Available-for-sale debt and other securities:	0	0
Recurring | Level 1 | Non-agency commercial mortgage-backed securities | Commercial
Assets:
Available-for-sale debt and other securities:	0	0
Recurring | Level 1 | Asset-backed securities and other debt securities
Assets:
Available-for-sale debt and other securities:	0	0
Trading debt securities	0	0
Liabilities:
Short positions	0	0
Recurring | Level 1 | Equity securities
Liabilities:
Short positions	42	21
Recurring | Level 2
Assets:
Available-for-sale debt and other securities:	34,562	34,409
Trading debt securities	484	594
Equity securities	29	34
Residential mortgage loans held for sale	445	574
Derivative Assets	2,112	2,388
Total assets	37,632	37,999
Liabilities:
Derivative Liabilities	2,140	2,566
Short positions	125	156
Total liabilities	2,265	2,722
Recurring | Level 2 | Interest rate contracts
Assets:
Derivative Assets	580	721
Liabilities:
Derivative Liabilities	747	939
Recurring | Level 2 | Foreign exchange contracts
Assets:
Derivative Assets	798	1,167
Liabilities:
Derivative Liabilities	758	1,120
Recurring | Level 2 | Equity contracts
Liabilities:
Derivative Liabilities	0	0
Recurring | Level 2 | Commodity contracts
Assets:
Derivative Assets	734	500
Liabilities:
Derivative Liabilities	635	507
Recurring | Level 2 | Servicing rights
Assets:
Servicing rights	0	0
Recurring | Level 2 | Residential Mortgage
Assets:
Residential mortgage loans	0	0
Recurring | Level 2 | U.S. Treasury and federal agencies securities
Assets:
Available-for-sale debt and other securities:	0	0
Trading debt securities	20	35
Liabilities:
Short positions	0	0
Recurring | Level 2 | Obligations of states and political subdivisions securities
Assets:
Trading debt securities	70	120
Recurring | Level 2 | Agency mortgage-backed securities | Residential Mortgage
Assets:
Available-for-sale debt and other securities:	6,601	5,681
Trading debt securities	26	10
Recurring | Level 2 | Agency mortgage-backed securities | Commercial
Assets:
Available-for-sale debt and other securities:	21,056	20,832
Recurring | Level 2 | Non-agency commercial mortgage-backed securities | Commercial
Assets:
Available-for-sale debt and other securities:	3,706	4,167
Recurring | Level 2 | Asset-backed securities and other debt securities
Assets:
Available-for-sale debt and other securities:	3,199	3,729
Trading debt securities	368	429
Liabilities:
Short positions	125	156
Recurring | Level 2 | Equity securities
Liabilities:
Short positions	0	0
Recurring | Level 3
Assets:
Available-for-sale debt and other securities:	0	0
Trading debt securities	0	0
Equity securities	0	0
Residential mortgage loans held for sale	0	0
Derivative Assets	5	2
Total assets	1,777	1,814
Liabilities:
Derivative Liabilities	178	175
Short positions	0	0
Total liabilities	178	175
Recurring | Level 3 | Interest rate contracts
Assets:
Derivative Assets	5	2
Liabilities:
Derivative Liabilities	5	5
Recurring | Level 3 | Foreign exchange contracts
Assets:
Derivative Assets	0	0
Liabilities:
Derivative Liabilities	0	0
Recurring | Level 3 | Equity contracts
Liabilities:
Derivative Liabilities	173	170
Recurring | Level 3 | Commodity contracts
Assets:
Derivative Assets	0	0
Liabilities:
Derivative Liabilities	0	0
Recurring | Level 3 | Servicing rights
Assets:
Servicing rights	1,663	1,704
Recurring | Level 3 | Residential Mortgage
Assets:
Residential mortgage loans	109	108
Recurring | Level 3 | U.S. Treasury and federal agencies securities
Assets:
Available-for-sale debt and other securities:	0	0
Trading debt securities	0	0
Liabilities:
Short positions	0	0
Recurring | Level 3 | Obligations of states and political subdivisions securities
Assets:
Trading debt securities	0	0
Recurring | Level 3 | Agency mortgage-backed securities | Residential Mortgage
Assets:
Available-for-sale debt and other securities:	0	0
Trading debt securities	0	0
Recurring | Level 3 | Agency mortgage-backed securities | Commercial
Assets:
Available-for-sale debt and other securities:	0	0
Recurring | Level 3 | Non-agency commercial mortgage-backed securities | Commercial
Assets:
Available-for-sale debt and other securities:	0	0
Recurring | Level 3 | Asset-backed securities and other debt securities
Assets:
Available-for-sale debt and other securities:	0	0
Trading debt securities	0	0
Liabilities:
Short positions	0	0
Recurring | Level 3 | Equity securities
Liabilities:
Short positions	$ 0	$ 0