Allowance for Credit Losses - Narrative (Details) $ in Millions	9 Months Ended
	Sep. 30, 2024 USD ($)
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit losses	$ 26,500
Net addition (reduction) to the allowance for credit losses	1,800
Consumer
Financing Receivable, Allowance for Credit Loss [Line Items]
Net addition (reduction) to the allowance for credit losses	1,500
Consumer | Card Services
Financing Receivable, Allowance for Credit Loss [Line Items]
Net addition (reduction) to the allowance for credit losses	1,700
Consumer | Home Lending
Financing Receivable, Allowance for Credit Loss [Line Items]
Net addition (reduction) to the allowance for credit losses	(125)
Wholesale
Financing Receivable, Allowance for Credit Loss [Line Items]
Net addition (reduction) to the allowance for credit losses	$ 196