Loans - Wholesale Loan Portfolio, Loans Secured by Real Estate (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024	Jun. 30, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 1,345,473	$ 1,299,590	$ 1,273,047
Wholesale
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 740,675	$ 690,396	$ 674,152
% of criticized to total retained loans secured by real estate	3.58%	3.67%
% of criticized nonaccrual loans to total retained loans secured by real estate	0.60%	0.57%
Wholesale \| Criticized nonaccrual
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 4,479	$ 3,942
Wholesale \| Secured by real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 164,222	$ 162,432
% of criticized to total retained loans secured by real estate	6.68%	6.61%
% of criticized nonaccrual loans to total retained loans secured by real estate	0.90%	0.89%
Wholesale \| Secured by real estate \| Criticized
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 10,971	$ 10,730
% of criticized to total retained loans secured by real estate	6.68%	6.61%
Wholesale \| Secured by real estate \| Criticized nonaccrual
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 1,477	$ 1,439
% of criticized nonaccrual loans to total retained loans secured by real estate	0.90%	0.89%
Wholesale \| Secured by real estate \| Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 102,012	$ 101,114
Wholesale \| Secured by real estate \| Multifamily \| Criticized
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 4,745	$ 4,700
% of criticized to total retained loans secured by real estate	4.65%	4.65%
Wholesale \| Secured by real estate \| Multifamily \| Criticized nonaccrual
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 373	$ 337
% of criticized nonaccrual loans to total retained loans secured by real estate	0.37%	0.33%
Wholesale \| Secured by real estate \| Other commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 62,210	$ 61,318
Wholesale \| Secured by real estate \| Other commercial \| Criticized
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 6,226	$ 6,030
% of criticized to total retained loans secured by real estate	10.01%	9.83%
Wholesale \| Secured by real estate \| Other commercial \| Criticized nonaccrual
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 1,104	$ 1,102
% of criticized nonaccrual loans to total retained loans secured by real estate	1.77%	1.80%

Accounts, Notes, Loans and Financing Receivable [Line Items]