Allowance for Credit Losses on Loans and Leases - Additional Information about Nonaccrual Loans (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Financing Receivable, Impaired [Line Items]
Total non-accrual loans with no related allowance	$ 2,123	$ 1,636
Total non-accrual loans with an allowance recorded, recorded investment	1,157	979
Total non-accrual loans with an allowance recorded, related allowance	209	164
Total non-accrual loans	3,280	2,615
Mortgage Loans Held for Investment | Multi-family
Financing Receivable, Impaired [Line Items]
Total non-accrual loans with no related allowance	1,563	1,092
Total non-accrual loans with an allowance recorded, recorded investment	798	663
Total non-accrual loans with an allowance recorded, related allowance	100	77
Total non-accrual loans	2,361	1,755
Mortgage Loans Held for Investment | Commercial real estate
Financing Receivable, Impaired [Line Items]
Total non-accrual loans with no related allowance	446	429
Total non-accrual loans with an allowance recorded, recorded investment	143	135
Total non-accrual loans with an allowance recorded, related allowance	35	31
Total non-accrual loans	589	564
Mortgage Loans Held for Investment | One-to-four family first mortgage
Financing Receivable, Impaired [Line Items]
Total non-accrual loans with no related allowance	67	61
Total non-accrual loans with an allowance recorded, recorded investment	10	9
Total non-accrual loans with an allowance recorded, related allowance	1	1
Total non-accrual loans	77	70
Mortgage Loans Held for Investment | Commercial and industrial
Financing Receivable, Impaired [Line Items]
Total non-accrual loans with an allowance recorded, related allowance		0
Total non-accrual loans		202
Other
Financing Receivable, Impaired [Line Items]
Total non-accrual loans with no related allowance	1	3
Total non-accrual loans with an allowance recorded, recorded investment	21	21
Total non-accrual loans with an allowance recorded, related allowance	20	55
Total non-accrual loans	22	24
Other | Commercial and industrial
Financing Receivable, Impaired [Line Items]
Total non-accrual loans with no related allowance	46	51
Total non-accrual loans with an allowance recorded, recorded investment	185	151
Total non-accrual loans with an allowance recorded, related allowance	53
Total non-accrual loans	$ 231