Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Assets:
Equity securities	$ 323	$ 317
Derivative assets	2,750	3,171
Liabilities:
Derivative liabilities	3,300	3,951
Residential Mortgage
Assets:
Residential mortgage loans	128	123	$ 145
Other securities
Liabilities:
FHLB, restricted stock holdings	396	381
FRB, restricted stock holdings	491	491
DTCC, restricted stock holdings	3	2
Level 3 | Interest rate contracts
Assets:
Derivative assets	11		8
Liabilities:
Derivative liabilities	8		$ 10
Recurring
Assets:
Available-for-sale debt and other securities	49,829	50,629
Trading debt securities	1,174	414
Equity securities	323	317
Residential mortgage loans held for sale	599	600
Derivative assets	2,757	3,173
Total assets	56,535	57,002
Liabilities:
Derivative liabilities	3,300	3,952
Short positions	222	178
Total liabilities	3,522	4,130
Recurring | Interest rate contracts
Assets:
Derivative assets	1,154	1,241
Liabilities:
Derivative liabilities	1,645	1,985
Recurring | Foreign exchange contracts
Assets:
Derivative assets	450	454
Liabilities:
Derivative liabilities	407	422
Recurring | Equity contracts
Liabilities:
Derivative liabilities	192	195
Recurring | Commodity contracts
Assets:
Derivative assets	1,153	1,478
Liabilities:
Derivative liabilities	1,056	1,350
Recurring | Servicing rights
Assets:
Servicing rights	1,725	1,746
Recurring | Residential Mortgage
Assets:
Residential mortgage loans	128	123
Recurring | U.S. Treasury and federal agencies securities
Assets:
Available-for-sale debt and other securities	2,689	2,495
Trading debt securities	687	45
Liabilities:
Short positions	74	66
Recurring | Obligations of states and political subdivisions securities
Assets:
Available-for-sale debt and other securities	3	18
Trading debt securities	49	14
Recurring | Agency mortgage-backed securities | Residential Mortgage
Assets:
Available-for-sale debt and other securities	11,073	11,237
Trading debt securities	11	8
Recurring | Agency mortgage-backed securities | Commercial
Assets:
Available-for-sale debt and other securities	26,183	26,322
Recurring | Non-agency mortgage-backed securities | Commercial
Assets:
Available-for-sale debt and other securities	4,550	4,715
Recurring | Asset-backed securities and other debt securities
Assets:
Available-for-sale debt and other securities	5,331	5,842
Trading debt securities	427	347
Liabilities:
Short positions	148	112
Recurring | Level 1
Assets:
Available-for-sale debt and other securities	2,689	2,495
Trading debt securities	669	23
Equity securities	311	306
Residential mortgage loans held for sale	0	0
Derivative assets	128	68
Total assets	3,797	2,892
Liabilities:
Derivative liabilities	42	99
Short positions	74	66
Total liabilities	116	165
Recurring | Level 1 | Interest rate contracts
Assets:
Derivative assets	3	12
Liabilities:
Derivative liabilities	8	7
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	125	56
Liabilities:
Derivative liabilities	34	92
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	2,689	2,495
Trading debt securities	669	23
Liabilities:
Short positions	74	66
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 2
Assets:
Available-for-sale debt and other securities	47,140	48,134
Trading debt securities	505	391
Equity securities	12	11
Residential mortgage loans held for sale	599	600
Derivative assets	2,618	3,098
Total assets	50,874	52,234
Liabilities:
Derivative liabilities	3,058	3,650
Short positions	148	112
Total liabilities	3,206	3,762
Recurring | Level 2 | Interest rate contracts
Assets:
Derivative assets	1,140	1,222
Liabilities:
Derivative liabilities	1,629	1,970
Recurring | Level 2 | Foreign exchange contracts
Assets:
Derivative assets	450	454
Liabilities:
Derivative liabilities	407	422
Recurring | Level 2 | Equity contracts
Liabilities:
Derivative liabilities	0	0
Recurring | Level 2 | Commodity contracts
Assets:
Derivative assets	1,028	1,422
Liabilities:
Derivative liabilities	1,022	1,258
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	18	22
Liabilities:
Short positions	0	0
Recurring | Level 2 | Obligations of states and political subdivisions securities
Assets:
Available-for-sale debt and other securities	3	18
Trading debt securities	49	14
Recurring | Level 2 | Agency mortgage-backed securities | Residential Mortgage
Assets:
Available-for-sale debt and other securities	11,073	11,237
Trading debt securities	11	8
Recurring | Level 2 | Agency mortgage-backed securities | Commercial
Assets:
Available-for-sale debt and other securities	26,183	26,322
Recurring | Level 2 | Non-agency mortgage-backed securities | Commercial
Assets:
Available-for-sale debt and other securities	4,550	4,715
Recurring | Level 2 | Asset-backed securities and other debt securities
Assets:
Available-for-sale debt and other securities	5,331	5,842
Trading debt securities	427	347
Liabilities:
Short positions	148	112
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	11	7
Total assets	1,864	1,876
Liabilities:
Derivative liabilities	200	203
Short positions	0	0
Total liabilities	200	203
Recurring | Level 3 | Interest rate contracts
Assets:
Derivative assets	11	7
Liabilities:
Derivative liabilities	8	8
Recurring | Level 3 | Foreign exchange contracts
Assets:
Derivative assets	0	0
Liabilities:
Derivative liabilities	0	0
Recurring | Level 3 | Equity contracts
Liabilities:
Derivative liabilities	192	195
Recurring | Level 3 | Commodity contracts
Assets:
Derivative assets	0	0
Liabilities:
Derivative liabilities	0	0
Recurring | Level 3 | Servicing rights
Assets:
Servicing rights	1,725	1,746
Recurring | Level 3 | Residential Mortgage
Assets:
Residential mortgage loans	128	123
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