Loans - Consumer, Excluding Credit Card Loan Portfolio, Residential Real Estate, Payment Status of FDMs (Details) - Consumer, excluding credit card - Residential real estate - USD ($) $ in Millions	Jun. 30, 2024	Jun. 30, 2023
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	$ 158	$ 75
Current
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	125	64
30–149 days past due
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	19	5
150 or more days past due
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	$ 14	$ 6