Fair Value Measurements - Fair Value of Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	$ 809	$ 701
Securities available for sale	42,437	45,364
Derivative assets, netting adjustments	(168)	(284)
Total derivative assets	2,757	1,962
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, netting adjustments	(2,568)	(1,526)
Other
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	2
U.S. Treasury, agencies and corporations
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	9,589	9,472
Other securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	1	0
Agency residential mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	4,379	5,122
Agency commercial mortgage-backed securities | Mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	9,424	9,651
Recurring
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	795	683
Commercial loans	14	18
Total trading account assets	809	701
Securities available for sale	42,437	45,364
Total other investments	82	105
Loans, net of unearned income (residential)	11	11
Loans held for sale (residential)	83	281
Derivative assets, gross	2,925	2,246
Derivative assets, netting adjustments	(168)	(284)
Total derivative assets	2,757	1,962
Total assets on a recurring basis at fair value	46,179	48,424
LIABILITIES MEASURED ON A RECURRING BASIS
Total liabilities on a recurring basis at fair value	1,641	749
Recurring | Short positions
LIABILITIES MEASURED ON A RECURRING BASIS
Short positions	709	588
Recurring | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	3,500	1,687
Derivative liabilities, netting adjustments	(2,568)	(1,526)
Total derivative liabilities	932	161
Recurring | Interest rate
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	274	807
Recurring | Interest rate | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	857	253
Recurring | Foreign exchange
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	143	81
Recurring | Foreign exchange | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	134	76
Recurring | Commodity
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	2,497	1,330
Recurring | Commodity | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	2,490	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	11	27
Recurring | Other | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	15	11
Recurring | Agency residential collateralized mortgage obligations
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	19,044	21,119
Recurring | Mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	117	44
Recurring | U.S. Treasury, agencies and corporations
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	627	530
Securities available for sale	9,589	9,472
Recurring | States and political subdivisions
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	38	96
Securities available for sale	0	0
Recurring | Other securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	13	13
Securities available for sale	1	0
Recurring | Agency residential mortgage-backed securities | Mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	4,379	5,122
Recurring | Agency commercial mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	9,424	9,651
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	41	46
Recurring | Equity Investments, Direct
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	8	33
Recurring | Equity Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	41	59
Recurring | Level 1
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	2	24
Loans, net of unearned income (residential)	0	0
Loans held for sale (residential)	0	0
Derivative assets, gross	119	71
Derivative assets, netting adjustments	0	0
Total derivative assets	119	71
Total assets on a recurring basis at fair value	121	95
LIABILITIES MEASURED ON A RECURRING BASIS
Total liabilities on a recurring basis at fair value	151	141
Recurring | Level 1 | Short positions
LIABILITIES MEASURED ON A RECURRING BASIS
Short positions	41	75
Recurring | Level 1 | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	110	66
Derivative liabilities, netting adjustments	0	0
Total derivative liabilities	110	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	119	71
Recurring | Level 1 | Foreign exchange | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	110	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 | Other securities
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 | 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	2	24
Recurring | Level 1 | Equity Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	2	24
Recurring | Level 2
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	795	683
Commercial loans	14	18
Total trading account assets	809	701
Securities available for sale	42,437	45,364
Total other investments	0	0
Loans, net of unearned income (residential)	0	0
Loans held for sale (residential)	83	281
Derivative assets, gross	2,806	2,136
Derivative assets, netting adjustments	0	0
Total derivative assets	2,806	2,136
Total assets on a recurring basis at fair value	46,135	48,482
LIABILITIES MEASURED ON A RECURRING BASIS
Total liabilities on a recurring basis at fair value	4,053	2,127
Recurring | Level 2 | Short positions
LIABILITIES MEASURED ON A RECURRING BASIS
Short positions	668	513
Recurring | Level 2 | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	3,385	1,614
Derivative liabilities, netting adjustments	0	0
Total derivative liabilities	3,385	1,614
Recurring | Level 2 | Interest rate
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	277	774
Recurring | Level 2 | Interest rate | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	857	253
Recurring | Level 2 | Foreign exchange
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	24	10
Recurring | Level 2 | Foreign exchange | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	24	10
Recurring | Level 2 | Commodity
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	2,497	1,330
Recurring | Level 2 | Commodity | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	2,490	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	9	22
Recurring | Level 2 | Other | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	14	11
Recurring | Level 2 | Agency residential collateralized mortgage obligations
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	19,044	21,119
Recurring | Level 2 | Mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	117	44
Recurring | Level 2 | U.S. Treasury, agencies and corporations
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	627	530
Securities available for sale	9,589	9,472
Recurring | Level 2 | States and political subdivisions
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	38	96
Securities available for sale	0	0
Recurring | Level 2 | Other securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	13	13
Securities available for sale	1	0
Recurring | Level 2 | Agency residential mortgage-backed securities | Mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	4,379	5,122
Recurring | Level 2 | Agency commercial mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	9,424	9,651
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	7	10
Loans, net of unearned income (residential)	11	11
Loans held for sale (residential)	0	0
Derivative assets, gross	(1)	39
Derivative assets, netting adjustments	0	0
Total derivative assets	(1)	39
Total assets on a recurring basis at fair value	17	60
LIABILITIES MEASURED ON A RECURRING BASIS
Total liabilities on a recurring basis at fair value	5	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	5	7
Derivative liabilities, netting adjustments	0	0
Total derivative liabilities	5	7
Recurring | Level 3 | Interest rate
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	(3)	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	1	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 | Other securities
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 | 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	6	9
Recurring | Level 3 | Equity Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	6	9
Recurring | Measured at NAV | Principal Investments, Indirect | Variable Interest Entity, Not Primary Beneficiary
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	40	45
Recurring | Measured at NAV | Equity Investments Direct, NAV
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	28	21
Recurring | Measured at NAV | Equity Investments Indirect, NAV
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	$ 5	$ 5