Fair Value Measurements - Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	$ 972	$ 1,283
Total securities available for sale	40,456	37,707
Loans, net of unearned income (residential)	105,902	104,260
Derivative assets	559	612
Netting adjustments	(329)	(363)
Total derivative assets	230	249
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	971	1,439
Netting adjustments	(334)	(411)
U.S. Treasury, agencies and corporations
ASSETS MEASURED ON A RECURRING BASIS
Total securities available for sale	8,208	8,904
Agency residential mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Total securities available for sale	19,434	15,169
Commercial Mortgage Backed Securities
ASSETS MEASURED ON A RECURRING BASIS
Total securities available for sale	4,035	4,410
Recurring
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	968	1,265
Commercial loans	4	18
Total trading account assets	972	1,283
Total securities available for sale	40,456	37,707
Total other investments	84	73
Loans, net of unearned income (residential)	10	10
Loans held for sale (residential)	62	93
Derivative assets	559	612
Netting adjustments	(329)	(363)
Total derivative assets	230	249
Total assets on a recurring basis at fair value	41,814	39,415
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	971	1,439
Netting adjustments	(334)	(411)
Total derivative liabilities	637	1,028
Total liabilities on a recurring basis at fair value	1,476	1,908
Recurring | Short positions
LIABILITIES MEASURED ON A RECURRING BASIS
Short positions	839	880
Recurring | Interest rate
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	164	110
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	574	965
Recurring | Foreign exchange
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	102	124
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	96	117
Recurring | Commodity
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	276	363
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	263	343
Recurring | Credit
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	0	0
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	8	0
Recurring | Other
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	17	15
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	30	14
Recurring | Agency residential collateralized mortgage obligations
ASSETS MEASURED ON A RECURRING BASIS
Total securities available for sale	8,779	9,224
Recurring | Other mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	199	183
Recurring | U.S. Treasury, agencies and corporations
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	550	930
Total securities available for sale	8,208	8,904
Recurring | States and political subdivisions
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	79	127
Recurring | Other securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	140	25
Total securities available for sale	0	0
Recurring | Agency residential mortgage-backed securities | Other mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Total securities available for sale	19,434	15,169
Recurring | Commercial Mortgage Backed Securities
ASSETS MEASURED ON A RECURRING BASIS
Total securities available for sale	4,035	4,410
Recurring | Indirect investments | Variable Interest Entity, Not Primary Beneficiary
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	11	14
Recurring | Principal Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	11	14
Recurring | Equity Investments, Direct
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	2	2
Recurring | Equity Investments Direct, NAV
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	68	54
Recurring | Equity Investments Indirect, NAV
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	3	3
Recurring | Equity Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	73	59
Level 1 | Indirect investments | Variable Interest Entity, Not Primary Beneficiary
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 1 | Recurring
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	1	0
Commercial loans	0	0
Total trading account assets	1	0
Total securities available for sale	0	0
Total other investments	0	0
Loans, net of unearned income (residential)	0	0
Loans held for sale (residential)	0	0
Derivative assets	57	93
Netting adjustments	0	0
Total derivative assets	57	93
Total assets on a recurring basis at fair value	58	93
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	51	85
Netting adjustments	0	0
Total derivative liabilities	51	85
Total liabilities on a recurring basis at fair value	535	192
Level 1 | Recurring | Short positions
LIABILITIES MEASURED ON A RECURRING BASIS
Short positions	484	107
Level 1 | Recurring | Interest rate
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	0	0
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	0	0
Level 1 | Recurring | Foreign exchange
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	57	93
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	51	85
Level 1 | Recurring | Commodity
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	0	0
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	0	0
Level 1 | Recurring | Credit
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	0	0
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	0	0
Level 1 | Recurring | Other
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	0	0
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	0	0
Level 1 | Recurring | Agency residential collateralized mortgage obligations
ASSETS MEASURED ON A RECURRING BASIS
Total securities available for sale	0	0
Level 1 | Recurring | Other mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Level 1 | Recurring | U.S. Treasury, agencies and corporations
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Total securities available for sale	0	0
Level 1 | Recurring | States and political subdivisions
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Level 1 | Recurring | Other securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	1	0
Total securities available for sale	0	0
Level 1 | Recurring | Agency residential mortgage-backed securities | Other mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Total securities available for sale	0	0
Level 1 | Recurring | Commercial Mortgage Backed Securities
ASSETS MEASURED ON A RECURRING BASIS
Total securities available for sale	0	0
Level 1 | Recurring | Principal Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 1 | Recurring | Equity Investments, Direct
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 1 | Recurring | Equity Investments Direct, NAV
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 1 | Recurring | Equity Investments Indirect, NAV
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 1 | Recurring | Equity Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 2 | Indirect investments | Variable Interest Entity, Not Primary Beneficiary
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 2 | Recurring
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	967	1,265
Commercial loans	4	18
Total trading account assets	971	1,283
Total securities available for sale	40,456	37,707
Total other investments	0	0
Loans, net of unearned income (residential)	0	0
Loans held for sale (residential)	62	93
Derivative assets	498	523
Netting adjustments	0	0
Total derivative assets	498	523
Total assets on a recurring basis at fair value	41,987	39,606
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	920	1,354
Netting adjustments	0	0
Total derivative liabilities	920	1,354
Total liabilities on a recurring basis at fair value	1,275	2,127
Level 2 | Recurring | Short positions
LIABILITIES MEASURED ON A RECURRING BASIS
Short positions	355	773
Level 2 | Recurring | Interest rate
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	161	114
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	574	965
Level 2 | Recurring | Foreign exchange
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	45	31
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	45	32
Level 2 | Recurring | Commodity
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	276	363
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	263	343
Level 2 | Recurring | Credit
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	0	0
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	8	0
Level 2 | Recurring | Other
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	16	15
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	30	14
Level 2 | Recurring | Agency residential collateralized mortgage obligations
ASSETS MEASURED ON A RECURRING BASIS
Total securities available for sale	8,779	9,224
Level 2 | Recurring | Other mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	199	183
Level 2 | Recurring | U.S. Treasury, agencies and corporations
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	550	930
Total securities available for sale	8,208	8,904
Level 2 | Recurring | States and political subdivisions
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	79	127
Level 2 | Recurring | Other securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	139	25
Total securities available for sale	0	0
Level 2 | Recurring | Agency residential mortgage-backed securities | Other mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Total securities available for sale	19,434	15,169
Level 2 | Recurring | Commercial Mortgage Backed Securities
ASSETS MEASURED ON A RECURRING BASIS
Total securities available for sale	4,035	4,410
Level 2 | Recurring | Principal Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 2 | Recurring | Equity Investments, Direct
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 2 | Recurring | Equity Investments Direct, NAV
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 2 | Recurring | Equity Investments Indirect, NAV
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 2 | Recurring | Equity Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 3 | Other
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	1
Level 3 | Indirect investments | Variable Interest Entity, Not Primary Beneficiary
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 3 | Recurring
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Commercial loans	0	0
Total trading account assets	0	0
Total securities available for sale	0	0
Total other investments	2	2
Loans, net of unearned income (residential)	10	10
Loans held for sale (residential)	0	0
Derivative assets	4	(4)
Netting adjustments	0	0
Total derivative assets	4	(4)
Total assets on a recurring basis at fair value	16	8
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	0	0
Netting adjustments	0	0
Total derivative liabilities	0	0
Total liabilities on a recurring basis at fair value	0	0
Level 3 | Recurring | Short positions
LIABILITIES MEASURED ON A RECURRING BASIS
Short positions	0	0
Level 3 | Recurring | Interest rate
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	3	(4)
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	0	0
Level 3 | Recurring | Foreign exchange
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	0	0
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	0	0
Level 3 | Recurring | Commodity
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	0	0
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	0	0
Level 3 | Recurring | Credit
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets	0	0
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	0	0
Level 3 | Recurring | Other
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets		0
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities	0	0
Level 3 | Recurring | Agency residential collateralized mortgage obligations
ASSETS MEASURED ON A RECURRING BASIS
Total securities available for sale	0	0
Level 3 | Recurring | Other mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Level 3 | Recurring | U.S. Treasury, agencies and corporations
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Total securities available for sale	0	0
Level 3 | Recurring | States and political subdivisions
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Level 3 | Recurring | Other securities
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Total securities available for sale	0	0
Level 3 | Recurring | Agency residential mortgage-backed securities | Other mortgage-backed securities
ASSETS MEASURED ON A RECURRING BASIS
Total securities available for sale	0	0
Level 3 | Recurring | Commercial Mortgage Backed Securities
ASSETS MEASURED ON A RECURRING BASIS
Total securities available for sale	0	0
Level 3 | Recurring | Principal Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 3 | Recurring | Equity Investments, Direct
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	2	2
Level 3 | Recurring | Equity Investments Direct, NAV
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 3 | Recurring | Equity Investments Indirect, NAV
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 3 | Recurring | Equity Investments
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	$ 2	$ 2