Loans - Consumer, Excluding Credit Card Loan Portfolio (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 1,084,850	$ 1,089,598	$ 1,018,397
Consumer, excluding credit card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	300,447	300,753	$ 296,161
Consumer, excluding credit card | Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	236,115	237,561
Consumer, excluding credit card | Auto and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 64,332	$ 63,192