OTHER ASSETS - Schedule of Other Assets (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Affordable housing tax credit and other unconsolidated investments	$ 2,099	$ 2,052
Accrued interest receivable	914	832
Fair value of derivative financial instruments	659	640
Pension assets	480	474
Right of use assets for operating leases, net	355	354
Income tax receivable	103	209
Counterparty receivables	79	114
Bank-owned life insurance	106	105
Nonmarketable equity securities	107	103
Other real estate owned	56	58
Mortgage servicing rights	25	25
Federal Home Loan Bank stock	20	20
Other	828	871
Total other assets	$ 5,831	$ 5,857