Loans, Lending Commitments and Related Allowance for Credit Losses - Past Due Loans Held for Investment before Allowance (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 214,139	$ 204,554
Past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	393	393
Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	6,764	6,758
Corporate | Past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	0	47
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	8,804	8,678
Commercial real estate | Past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	228	185
Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	63,161	60,375
Residential real estate | Past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	165	160
Securities-based lending and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	90,541	89,245
Securities-based lending and Other | Past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 0	$ 1