Loans - Consumer, Excluding Credit Card Loan Portfolio, Residential Real Estate, Payment Status of FDMs and Defaults of FDMs (Details) - Consumer, excluding credit card - Residential real estate - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	$ 1,062	$ 211	$ 1,062	$ 211
FDM's that defaulted	0	44	0	74
Current
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	356	143	356	143
30–149 days past due
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	76	45	76	45
150 or more days past due
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	$ 630	$ 23	$ 630	$ 23