Fair Value Accounting - Schedule of Carrying and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Financial assets
Securities held to maturity	$ 2,539	$ 2,591
Loans held for sale	251	97
Financial liabilities
FHLB advances and other borrowings	5,741	2,205
Level 1
Financial assets
Securities purchased with agreement to resell	0	0
Securities held to maturity	19	20
Loans held for sale	0	0
Loans, net	0	0
Financial liabilities
Deposits and securities sold under agreements to repurchase	0	0
FHLB advances and other borrowings	0	0
Level 2
Financial assets
Securities purchased with agreement to resell	0	0
Securities held to maturity	2,322	2,390
Loans held for sale	205	98
Loans, net	0	0
Financial liabilities
Deposits and securities sold under agreements to repurchase	0	0
FHLB advances and other borrowings	0	0
Level 3
Financial assets
Securities purchased with agreement to resell	86	96
Securities held to maturity	0	0
Loans held for sale	0	0
Loans, net	83,152	38,288
Financial liabilities
Deposits and securities sold under agreements to repurchase	100,418	46,735
FHLB advances and other borrowings	5,769	2,232
Carrying Value
Financial assets
Securities purchased with agreement to resell	86	96
Securities held to maturity	2,539	2,591
Loans held for sale	205	97
Loans, net	84,255	38,712
Financial liabilities
Deposits and securities sold under agreements to repurchase	100,411	47,717
FHLB advances and other borrowings	5,741	2,205
Fair Value
Financial assets
Securities purchased with agreement to resell	86	96
Securities held to maturity	2,341	2,410
Loans held for sale	205	98
Loans, net	83,152	38,288
Financial liabilities
Deposits and securities sold under agreements to repurchase	100,418	46,735
FHLB advances and other borrowings	$ 5,769	$ 2,232

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Federal Home Loan Bank (FHLB) Advances And Other Borrowings

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