Loans, Lending Commitments and Related Allowance for Credit Losses - Past Due Loans Held for Investment Modified in the Last 12 Months (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Financing Receivable, Modified, Subsequent Default [Line Items]
Total loans	$ 214,139	$ 204,554
Total
Financing Receivable, Modified, Subsequent Default [Line Items]
Total loans	67
30-89 Days Past Due
Financing Receivable, Modified, Subsequent Default [Line Items]
Total loans	67
90+ Days Past Due
Financing Receivable, Modified, Subsequent Default [Line Items]
Total loans	0
Commercial real estate
Financing Receivable, Modified, Subsequent Default [Line Items]
Total loans	8,804	$ 8,678
Commercial real estate | Total
Financing Receivable, Modified, Subsequent Default [Line Items]
Total loans	67
Commercial real estate | 30-89 Days Past Due
Financing Receivable, Modified, Subsequent Default [Line Items]
Total loans	67
Commercial real estate | 90+ Days Past Due
Financing Receivable, Modified, Subsequent Default [Line Items]
Total loans	$ 0