Fair Value Measurements - Fair Value of Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	$ 1,068	$ 701
Securities available for sale	40,000	45,364
Loans, net of unearned income	116,191	101,854
Derivative assets, netting adjustments	(720)	(284)
Total derivative assets	1,601	1,962
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, netting adjustments	(1,925)	(1,526)
Other
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	0
U.S. Treasury, agencies and corporations
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	9,386	9,472
Agency residential mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	3,985	5,122
Agency commercial mortgage-backed securities | Mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	9,391	9,651
Other securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	1	0
Recurring
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	1,062	683
Commercial loans	6	18
Total trading account assets	1,068	701
Securities available for sale	40,000	45,364
Total other investments	75	105
Loans, net of unearned income	9	11
Loans held for sale (residential)	61	281
Derivative assets, gross	2,321	2,246
Derivative assets, netting adjustments	(720)	(284)
Total derivative assets	1,601	1,962
Total assets on a recurring basis at fair value	42,814	48,424
LIABILITIES MEASURED ON A RECURRING BASIS
Total liabilities on a recurring basis at fair value	2,426	749
Recurring | Short positions
LIABILITIES MEASURED ON A RECURRING BASIS
Short positions	826	588
Recurring | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	3,525	1,687
Derivative liabilities, netting adjustments	(1,925)	(1,526)
Total derivative liabilities	1,600	161
Recurring | Interest rate
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	219	807
Recurring | Interest rate | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	1,429	253
Recurring | Foreign exchange
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	225	81
Recurring | Foreign exchange | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	217	76
Recurring | Commodity
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	1,857	1,330
Recurring | Commodity | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	1,838	1,335
Recurring | Credit
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	0	1
Recurring | Credit | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	4	12
Recurring | Other
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	20	27
Recurring | Other | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	37	11
Recurring | Agency residential collateralized mortgage obligations
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	17,237	21,119
Recurring | Mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	133	44
Recurring | U.S. Treasury, agencies and corporations
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	847	530
Securities available for sale	9,386	9,472
Recurring | States and political subdivisions
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	68	96
Securities available for sale	0	0
Recurring | Agency residential mortgage-backed securities | Mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	3,985	5,122
Recurring | Agency commercial mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	9,391	9,651
Recurring | Other securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	14	13
Securities available for sale	1	0
Recurring | Principal investments, Direct
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	1	1
Recurring | Principal Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	37	46
Recurring | Equity Investments, Direct
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	5	33
Recurring | Equity Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	38	59
Recurring | Level 1
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	2	0
Commercial loans	0	0
Total trading account assets	2	0
Securities available for sale	0	0
Total other investments	3	24
Loans, net of unearned income	0	0
Loans held for sale (residential)	0	0
Derivative assets, gross	180	71
Derivative assets, netting adjustments	0	0
Total derivative assets	180	71
Total assets on a recurring basis at fair value	185	95
LIABILITIES MEASURED ON A RECURRING BASIS
Total liabilities on a recurring basis at fair value	315	141
Recurring | Level 1 | Short positions
LIABILITIES MEASURED ON A RECURRING BASIS
Short positions	143	75
Recurring | Level 1 | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	172	66
Derivative liabilities, netting adjustments	0	0
Total derivative liabilities	172	66
Recurring | Level 1 | Interest rate
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	0	0
Recurring | Level 1 | Interest rate | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	0	0
Recurring | Level 1 | Foreign exchange
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	180	71
Recurring | Level 1 | Foreign exchange | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	172	66
Recurring | Level 1 | Commodity
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	0	0
Recurring | Level 1 | Commodity | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	0	0
Recurring | Level 1 | Credit
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	0	0
Recurring | Level 1 | Credit | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	0	0
Recurring | Level 1 | Other
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	0	0
Recurring | Level 1 | Other | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	0	0
Recurring | Level 1 | Agency residential collateralized mortgage obligations
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	0	0
Recurring | Level 1 | Mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Recurring | Level 1 | U.S. Treasury, agencies and corporations
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Securities available for sale	0	0
Recurring | Level 1 | States and political subdivisions
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Securities available for sale	0	0
Recurring | Level 1 | Agency residential mortgage-backed securities | Mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	0	0
Recurring | Level 1 | Agency commercial mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	0	0
Recurring | Level 1 | Other securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	2	0
Securities available for sale	0	0
Recurring | Level 1 | Principal investments, Direct
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Recurring | Level 1 | Principal Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Recurring | Level 1 | Equity Investments, Direct
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	3	24
Recurring | Level 1 | Equity Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	3	24
Recurring | Level 2
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	1,060	683
Commercial loans	6	18
Total trading account assets	1,066	701
Securities available for sale	40,000	45,364
Total other investments	0	0
Loans, net of unearned income	0	0
Loans held for sale (residential)	61	281
Derivative assets, gross	2,148	2,136
Derivative assets, netting adjustments	0	0
Total derivative assets	2,148	2,136
Total assets on a recurring basis at fair value	43,275	48,482
LIABILITIES MEASURED ON A RECURRING BASIS
Total liabilities on a recurring basis at fair value	4,029	2,127
Recurring | Level 2 | Short positions
LIABILITIES MEASURED ON A RECURRING BASIS
Short positions	683	513
Recurring | Level 2 | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	3,346	1,614
Derivative liabilities, netting adjustments	0	0
Total derivative liabilities	3,346	1,614
Recurring | Level 2 | Interest rate
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	227	774
Recurring | Level 2 | Interest rate | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	1,429	253
Recurring | Level 2 | Foreign exchange
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	45	10
Recurring | Level 2 | Foreign exchange | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	45	10
Recurring | Level 2 | Commodity
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	1,857	1,330
Recurring | Level 2 | Commodity | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	1,838	1,335
Recurring | Level 2 | Credit
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	0	0
Recurring | Level 2 | Credit | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	0	5
Recurring | Level 2 | Other
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	20	22
Recurring | Level 2 | Other | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	34	11
Recurring | Level 2 | Agency residential collateralized mortgage obligations
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	17,237	21,119
Recurring | Level 2 | Mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	133	44
Recurring | Level 2 | U.S. Treasury, agencies and corporations
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	847	530
Securities available for sale	9,386	9,472
Recurring | Level 2 | States and political subdivisions
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	68	96
Securities available for sale	0	0
Recurring | Level 2 | Agency residential mortgage-backed securities | Mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	3,985	5,122
Recurring | Level 2 | Agency commercial mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	9,391	9,651
Recurring | Level 2 | Other securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	12	13
Securities available for sale	1	0
Recurring | Level 2 | Principal investments, Direct
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Recurring | Level 2 | Principal Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Recurring | Level 2 | Equity Investments, Direct
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Recurring | Level 2 | Equity Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Recurring | Level 3
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Commercial loans	0	0
Total trading account assets	0	0
Securities available for sale	0	0
Total other investments	3	10
Loans, net of unearned income	9	11
Loans held for sale (residential)	0	0
Derivative assets, gross	(8)	39
Derivative assets, netting adjustments	0	0
Total derivative assets	(8)	39
Total assets on a recurring basis at fair value	4	60
LIABILITIES MEASURED ON A RECURRING BASIS
Total liabilities on a recurring basis at fair value	7	7
Recurring | Level 3 | Short positions
LIABILITIES MEASURED ON A RECURRING BASIS
Short positions	0	0
Recurring | Level 3 | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	7	7
Derivative liabilities, netting adjustments	0	0
Total derivative liabilities	7	7
Recurring | Level 3 | Interest rate
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	(8)	33
Recurring | Level 3 | Interest rate | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	0	0
Recurring | Level 3 | Foreign exchange
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	0	0
Recurring | Level 3 | Foreign exchange | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	0	0
Recurring | Level 3 | Commodity
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	0	0
Recurring | Level 3 | Commodity | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	0	0
Recurring | Level 3 | Credit
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	0	1
Recurring | Level 3 | Credit | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	4	7
Recurring | Level 3 | Other
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross		5
Recurring | Level 3 | Other | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	3	0
Recurring | Level 3 | Agency residential collateralized mortgage obligations
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	0	0
Recurring | Level 3 | Mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Recurring | Level 3 | U.S. Treasury, agencies and corporations
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Securities available for sale	0	0
Recurring | Level 3 | States and political subdivisions
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Securities available for sale	0	0
Recurring | Level 3 | Agency residential mortgage-backed securities | Mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	0	0
Recurring | Level 3 | Agency commercial mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	0	0
Recurring | Level 3 | Other securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Securities available for sale	0	0
Recurring | Level 3 | Principal investments, Direct
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	1	1
Recurring | Level 3 | Principal Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	1	1
Recurring | Level 3 | Equity Investments, Direct
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	2	9
Recurring | Level 3 | Equity Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	2	9
Recurring | Measured at NAV | Principal Investments, Indirect | Variable Interest Entity, Not Primary Beneficiary
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	36	45
Recurring | Measured at NAV | Equity Investments Direct, NAV
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	29	21
Recurring | Measured at NAV | Equity Investments Indirect, NAV
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	$ 4	$ 5