Loans, Lending Commitments and Related Allowance for Credit Losses - Past Due Loans Held for Investment before Allowance (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$ 277,857	$ 269,852
Past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	387	468
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	8,300	8,039
Commercial real estate \| Past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	187	129
Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	73,529	72,403
Residential real estate \| Past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	200	298
Securities-based lending and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	117,084	112,984
Securities-based lending and Other \| Past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$ 0	$ 41