Loans - Wholesale Loan Portfolio, Real Estate Class of Loans (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 1,018,397	$ 1,010,206	$ 948,642
Wholesale
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 569,953	$ 560,354	$ 514,478
% of criticized to total retained loans secured by real estate	2.66%	2.39%
% of criticized nonaccrual loans to total retained loans secured by real estate	0.40%	0.37%
Wholesale | Criticized nonaccrual
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 2,289	$ 2,054
Wholesale | Secured by real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 120,367	$ 118,835
% of criticized to total retained loans secured by real estate	3.51%	3.34%
% of criticized nonaccrual loans to total retained loans secured by real estate	0.31%	0.27%
Wholesale | Secured by real estate | Criticized
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 4,227	$ 3,971
% of criticized to total retained loans secured by real estate	3.51%	3.34%
Wholesale | Secured by real estate | Criticized nonaccrual
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 369	$ 326
% of criticized nonaccrual loans to total retained loans secured by real estate	0.31%	0.27%
Wholesale | Secured by real estate | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 75,194	$ 73,801
Wholesale | Secured by real estate | Multifamily | Criticized
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 1,850	$ 1,671
% of criticized to total retained loans secured by real estate	2.46%	2.26%
Wholesale | Secured by real estate | Multifamily | Criticized nonaccrual
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 82	$ 91
% of criticized nonaccrual loans to total retained loans secured by real estate	0.11%	0.12%
Wholesale | Secured by real estate | Other commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 45,173	$ 45,034
Wholesale | Secured by real estate | Other commercial | Criticized
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 2,377	$ 2,300
% of criticized to total retained loans secured by real estate	5.26%	5.11%
Wholesale | Secured by real estate | Other commercial | Criticized nonaccrual
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 287	$ 235
% of criticized nonaccrual loans to total retained loans secured by real estate	0.64%	0.52%
Wholesale | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 155,197	$ 145,691
% of criticized to total retained loans secured by real estate	5.81%	5.40%
% of criticized nonaccrual loans to total retained loans secured by real estate	0.74%	0.67%
Wholesale | Commercial and industrial | Criticized nonaccrual
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 1,148	$ 969
Wholesale | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 294,389	$ 295,828
% of criticized to total retained loans secured by real estate	0.66%	0.52%
% of criticized nonaccrual loans to total retained loans secured by real estate	0.26%	0.26%
Wholesale | Other | Criticized nonaccrual
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 772	$ 759