Other Assets - Components of Other Assets (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Affordable housing tax credit and other unconsolidated investments	$ 1,973	$ 762
Right of use assets for operating leases, net	403	345
Pension assets	364	343
Accrued interest receivable	833	329
Income tax receivable	518	275
Federal Home Loan Bank stock	19	197
Fair value of derivative financial instruments	904	159
Bank-owned life insurance	104	586
Counterparty receivables	74	98
Nonmarketable equity securities	95	58
Other real estate owned	60	47
Mortgage servicing rights	25	25
Other	840	1,145
Total other assets	$ 6,212	4,369
Other Assets, Miscellaneous
Other Assets [Line Items]
Bank owned life insurance, amount terminated but not cash-settled		$ 607