Fair Value Measurements - Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	$ 1,177	$ 829
Securities available for sale	37,908	39,117
Loans, net of unearned income (residential)	119,011	119,394
Netting adjustments	(967)	(757)
Total derivative assets	256	1,024
LIABILITIES MEASURED ON A RECURRING BASIS
Netting adjustments	(751)	(1,262)
Other
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	1
U.S. Treasury, agencies and corporations
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	9,489	9,415
Agency residential mortgage-backed securities | Mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	3,749	3,920
Agency commercial mortgage-backed securities | Mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	9,055	9,349
Other securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	0	0
Recurring
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	1,175	815
Commercial loans	2	14
Total trading account assets	1,177	829
Securities available for sale	37,908	39,117
Total other investments	59	77
Loans, net of unearned income (residential)	9	9
Loans held for sale (residential)	67	24
Derivative assets	1,223	1,781
Netting adjustments	(967)	(757)
Total derivative assets	256	1,024
Total assets on a recurring basis at fair value	39,476	41,080
LIABILITIES MEASURED ON A RECURRING BASIS
Total liabilities on a recurring basis at fair value	2,247	2,123
Recurring | Short positions
LIABILITIES MEASURED ON A RECURRING BASIS
Short positions	699	635
Recurring | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	2,299	2,750
Netting adjustments	(751)	(1,262)
Total derivative liabilities	1,548	1,488
Recurring | Interest rate
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	207	303
Recurring | Interest rate | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	1,321	1,307
Recurring | Foreign exchange
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	141	136
Recurring | Foreign exchange | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	123	131
Recurring | Commodity
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	867	1,328
Recurring | Commodity | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	842	1,304
Recurring | Credit
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	0	1
Recurring | Credit | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	9	3
Recurring | Other
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	8	13
Recurring | Other | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	4	5
Recurring | Agency residential collateralized mortgage obligations
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	15,615	16,433
Recurring | Mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	242	84
Recurring | U.S. Treasury, agencies and corporations
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	854	698
Securities available for sale	9,489	9,415
Recurring | States and political subdivisions
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	78	33
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	3,749	3,920
Recurring | Agency commercial mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	9,055	9,349
Recurring | Other securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	1	0
Securities available for sale	0	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	19	35
Recurring | Equity Investments, Direct
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	2	6
Recurring | Equity Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	40	42
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	0	4
Loans, net of unearned income (residential)	0	0
Loans held for sale (residential)	0	0
Derivative assets	123	112
Netting adjustments	0	0
Total derivative assets	123	112
Total assets on a recurring basis at fair value	123	116
LIABILITIES MEASURED ON A RECURRING BASIS
Total liabilities on a recurring basis at fair value	116	233
Recurring | Level 1 | Short positions
LIABILITIES MEASURED ON A RECURRING BASIS
Short positions	11	126
Recurring | Level 1 | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	105	107
Netting adjustments	0	0
Total derivative liabilities	105	107
Recurring | Level 1 | Interest rate
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	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	123	112
Recurring | Level 1 | Foreign exchange | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	105	107
Recurring | Level 1 | Commodity
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	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	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	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	0	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, Indirect
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	0	4
Recurring | Level 1 | Equity Investments Direct, NAV
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Recurring | Level 1 | Equity Investments Indirect, NAV
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Recurring | Level 1 | Equity Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	4
Recurring | Level 2
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	1,175	815
Commercial loans	2	14
Total trading account assets	1,177	829
Securities available for sale	37,908	39,117
Total other investments	0	0
Loans, net of unearned income (residential)	0	0
Loans held for sale (residential)	67	24
Derivative assets	1,094	1,666
Netting adjustments	0	0
Total derivative assets	1,094	1,666
Total assets on a recurring basis at fair value	40,246	41,636
LIABILITIES MEASURED ON A RECURRING BASIS
Total liabilities on a recurring basis at fair value	2,882	3,149
Recurring | Level 2 | Short positions
LIABILITIES MEASURED ON A RECURRING BASIS
Short positions	688	509
Recurring | Level 2 | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	2,194	2,640
Netting adjustments	0	0
Total derivative liabilities	2,194	2,640
Recurring | Level 2 | Interest rate
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	202	301
Recurring | Level 2 | Interest rate | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	1,321	1,307
Recurring | Level 2 | Foreign exchange
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	18	23
Recurring | Level 2 | Foreign exchange | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	18	24
Recurring | Level 2 | Commodity
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	867	1,328
Recurring | Level 2 | Commodity | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	842	1,304
Recurring | Level 2 | Credit
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	0	0
Recurring | Level 2 | Credit | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	9	0
Recurring | Level 2 | Other
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	7	13
Recurring | Level 2 | Other | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	4	5
Recurring | Level 2 | Agency residential collateralized mortgage obligations
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	15,615	16,433
Recurring | Level 2 | Mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	242	84
Recurring | Level 2 | U.S. Treasury, agencies and corporations
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	854	698
Securities available for sale	9,489	9,415
Recurring | Level 2 | States and political subdivisions
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	78	33
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	3,749	3,920
Recurring | Level 2 | Agency commercial mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	9,055	9,349
Recurring | Level 2 | Other securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	1	0
Securities available for sale	0	0
Recurring | Level 2 | Principal investments, Direct
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Recurring | Level 2 | Principal Investments, Indirect
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 Direct, NAV
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Recurring | Level 2 | Equity Investments Indirect, NAV
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	3
Loans, net of unearned income (residential)	9	9
Loans held for sale (residential)	0	0
Derivative assets	6	3
Netting adjustments	0	0
Total derivative assets	6	3
Total assets on a recurring basis at fair value	18	15
LIABILITIES MEASURED ON A RECURRING BASIS
Total liabilities on a recurring basis at fair value	0	3
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	0	3
Netting adjustments	0	0
Total derivative liabilities	0	3
Recurring | Level 3 | Interest rate
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	5	2
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	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	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	0	1
Recurring | Level 3 | Credit | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	0	3
Recurring | Level 3 | Other
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets		0
Recurring | Level 3 | Other | Long positions
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	0	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, Indirect
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
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	2
Recurring | Level 3 | Equity Investments Direct, NAV
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Recurring | Level 3 | Equity Investments Indirect, NAV
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Recurring | Level 3 | Equity Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	2	2
Recurring | Measured at NAV | Principal Investments, Indirect | Variable Interest Entity, Not Primary Beneficiary
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	18	34
Recurring | Measured at NAV | Equity Investments Direct, NAV
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	34	32
Recurring | Measured at NAV | Equity Investments Indirect, NAV
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	$ 4	$ 4