Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Assets:
Available-for-sale debt and other securities	$ 39,547	$ 50,419
Equity securities	341	613
Derivative assets	2,472	2,677
Liabilities:
Total derivative liabilities	$ 2,798	$ 2,999
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other assets	Other assets	Other assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other liabilities	Other liabilities	Other liabilities
Residential mortgage
Assets:
Residential mortgage loans	$ 108	$ 116
U.S. Treasury and federal agencies securities
Assets:
Available-for-sale debt and other securities	4,360	4,336
Obligations of states and political subdivisions securities
Assets:
Available-for-sale debt and other securities	0	2
Asset-backed securities and other debt securities
Assets:
Available-for-sale debt and other securities	3,729	4,912
Other securities
Assets:
Available-for-sale debt and other securities	778	722
Liabilities:
FHLB, restricted stock holdings	276	224
FRB, restricted stock holdings	500	496
DTCC, restricted stock holdings	2	2
Level 3     | Interest rate contracts
Assets:
Derivative assets	2	6	$ 7
Liabilities:
Total derivative liabilities	5	6	$ 8
Recurring
Assets:
Available-for-sale debt and other securities	38,769	49,697
Trading debt securities	1,185	899
Equity securities	341	613
Residential mortgage loans held for sale	574	334
Derivative assets	2,472	2,677
Total assets	45,153	56,073
Liabilities:
Total derivative liabilities	2,798	2,999
Short positions	316	107
Total liabilities	3,114	3,106
Recurring | Interest rate contracts
Assets:
Derivative assets	730	983
Liabilities:
Total derivative liabilities	944	1,213
Recurring | Foreign exchange contracts
Assets:
Derivative assets	1,167	643
Liabilities:
Total derivative liabilities	1,120	600
Recurring | Equity contracts
Liabilities:
Total derivative liabilities	170	168
Recurring | Commodity contracts
Assets:
Derivative assets	575	1,051
Liabilities:
Total derivative liabilities	564	1,018
Recurring | Servicing rights
Assets:
Servicing rights	1,704	1,737
Recurring | Residential mortgage
Assets:
Residential mortgage loans	108	116
Recurring | U.S. Treasury and federal agencies securities
Assets:
Available-for-sale debt and other securities	4,360	4,336
Trading debt securities	626	647
Liabilities:
Short positions	139	31
Recurring | Obligations of states and political subdivisions securities
Assets:
Available-for-sale debt and other securities	0	2
Trading debt securities	120	39
Recurring | Agency mortgage-backed securities | Residential mortgage
Assets:
Available-for-sale debt and other securities	5,681	10,282
Trading debt securities	10	6
Recurring | Agency mortgage-backed securities | Commercial
Assets:
Available-for-sale debt and other securities	20,832	25,720
Recurring | Non-agency mortgage-backed securities | Commercial
Assets:
Available-for-sale debt and other securities	4,167	4,445
Recurring | Asset-backed securities and other debt securities
Assets:
Available-for-sale debt and other securities	3,729	4,912
Trading debt securities	429	207
Liabilities:
Short positions	156	76
Recurring | Equity securities
Liabilities:
Short positions	21
Recurring | Level 1
Assets:
Available-for-sale debt and other securities	4,360	4,336
Trading debt securities	591	640
Equity securities	307	600
Residential mortgage loans held for sale	0	0
Derivative assets	82	205
Total assets	5,340	5,781
Liabilities:
Total derivative liabilities	57	33
Short positions	160	31
Total liabilities	217	64
Recurring | Level 1 | Interest rate contracts
Assets:
Derivative assets	7	0
Liabilities:
Total derivative liabilities	0	5
Recurring | Level 1 | Foreign exchange contracts
Assets:
Derivative assets	0	0
Liabilities:
Total derivative liabilities	0	0
Recurring | Level 1 | Equity contracts
Liabilities:
Total derivative liabilities	0	0
Recurring | Level 1 | Commodity contracts
Assets:
Derivative assets	75	205
Liabilities:
Total derivative liabilities	57	28
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	4,360	4,336
Trading debt securities	591	640
Liabilities:
Short positions	139	31
Recurring | Level 1 | Obligations of states and political subdivisions securities
Assets:
Available-for-sale debt and other securities	0	0
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 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	21
Recurring | Level 2
Assets:
Available-for-sale debt and other securities	34,409	45,361
Trading debt securities	594	259
Equity securities	34	13
Residential mortgage loans held for sale	574	334
Derivative assets	2,388	2,466
Total assets	37,999	48,433
Liabilities:
Total derivative liabilities	2,566	2,792
Short positions	156	76
Total liabilities	2,722	2,868
Recurring | Level 2 | Interest rate contracts
Assets:
Derivative assets	721	977
Liabilities:
Total derivative liabilities	939	1,202
Recurring | Level 2 | Foreign exchange contracts
Assets:
Derivative assets	1,167	643
Liabilities:
Total derivative liabilities	1,120	600
Recurring | Level 2 | Equity contracts
Liabilities:
Total derivative liabilities	0	0
Recurring | Level 2 | Commodity contracts
Assets:
Derivative assets	500	846
Liabilities:
Total derivative liabilities	507	990
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	35	7
Liabilities:
Short positions	0	0
Recurring | Level 2 | Obligations of states and political subdivisions securities
Assets:
Available-for-sale debt and other securities	0	2
Trading debt securities	120	39
Recurring | Level 2 | Agency mortgage-backed securities | Residential mortgage
Assets:
Available-for-sale debt and other securities	5,681	10,282
Trading debt securities	10	6
Recurring | Level 2 | Agency mortgage-backed securities | Commercial
Assets:
Available-for-sale debt and other securities	20,832	25,720
Recurring | Level 2 | Non-agency mortgage-backed securities | Commercial
Assets:
Available-for-sale debt and other securities	4,167	4,445
Recurring | Level 2 | Asset-backed securities and other debt securities
Assets:
Available-for-sale debt and other securities	3,729	4,912
Trading debt securities	429	207
Liabilities:
Short positions	156	76
Recurring | Level 2 | Equity securities
Liabilities:
Short positions	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	2	6
Total assets	1,814	1,859
Liabilities:
Total derivative liabilities	175	174
Short positions	0	0
Total liabilities	175	174
Recurring | Level 3     | Interest rate contracts
Assets:
Derivative assets	2	6
Liabilities:
Total derivative liabilities	5	6
Recurring | Level 3     | Foreign exchange contracts
Assets:
Derivative assets	0	0
Liabilities:
Total derivative liabilities	0	0
Recurring | Level 3     | Equity contracts
Liabilities:
Total derivative liabilities	170	168
Recurring | Level 3     | Commodity contracts
Assets:
Derivative assets	0	0
Liabilities:
Total derivative liabilities	0	0
Recurring | Level 3     | Servicing rights
Assets:
Servicing rights	1,704	1,737
Recurring | Level 3     | Residential mortgage
Assets:
Residential mortgage loans	108	116
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:
Available-for-sale debt and other securities	0	0
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 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