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, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	$ 211	$ 110	$ 211	$ 110
FDM's that defaulted	44	0	74	0
Current
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	143	90	143	90
30–149 days past due
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	45	13	45	13
150 or more days past due
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	$ 23	$ 7	$ 23	$ 7