Loans and Related Allowance for Credit Losses - Subsequently Defaulted FDM (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2024
Financing Receivable [Line Items]
Subsequently default	$ 102	$ 150
Term Extension
Financing Receivable [Line Items]
Subsequently default	14	27
Payment Delay
Financing Receivable [Line Items]
Subsequently default	40	62
Repayment Plan
Financing Receivable [Line Items]
Subsequently default	7	17
Payment Delay and Term Extension
Financing Receivable [Line Items]
Subsequently default	37	37
Other
Financing Receivable [Line Items]
Subsequently default	4	7
Total commercial
Financing Receivable [Line Items]
Subsequently default	84	106
Total commercial | Term Extension
Financing Receivable [Line Items]
Subsequently default	14	27
Total commercial | Payment Delay
Financing Receivable [Line Items]
Subsequently default	33	42
Total commercial | Payment Delay and Term Extension
Financing Receivable [Line Items]
Subsequently default	37	37
Total commercial | Commercial and industrial
Financing Receivable [Line Items]
Subsequently default	15	35
Total commercial | Commercial and industrial | Term Extension
Financing Receivable [Line Items]
Subsequently default	14	26
Total commercial | Commercial and industrial | Payment Delay
Financing Receivable [Line Items]
Subsequently default	1	9
Total commercial | Commercial real estate
Financing Receivable [Line Items]
Subsequently default	69	71
Total commercial | Commercial real estate | Term Extension
Financing Receivable [Line Items]
Subsequently default		1
Total commercial | Commercial real estate | Payment Delay
Financing Receivable [Line Items]
Subsequently default	32	33
Total commercial | Commercial real estate | Payment Delay and Term Extension
Financing Receivable [Line Items]
Subsequently default	37	37
Total consumer
Financing Receivable [Line Items]
Subsequently default	18	44
Total consumer | Payment Delay
Financing Receivable [Line Items]
Subsequently default	7	20
Total consumer | Repayment Plan
Financing Receivable [Line Items]
Subsequently default	7	17
Total consumer | Other
Financing Receivable [Line Items]
Subsequently default	4	7
Total consumer | Residential real estate
Financing Receivable [Line Items]
Subsequently default	7	21
Total consumer | Residential real estate | Payment Delay
Financing Receivable [Line Items]
Subsequently default	6	19
Total consumer | Residential real estate | Other
Financing Receivable [Line Items]
Subsequently default	1	2
Total consumer | Home equity
Financing Receivable [Line Items]
Subsequently default	4	7
Total consumer | Home equity | Payment Delay
Financing Receivable [Line Items]
Subsequently default	1	1
Total consumer | Home equity | Repayment Plan
Financing Receivable [Line Items]
Subsequently default		1
Total consumer | Home equity | Other
Financing Receivable [Line Items]
Subsequently default	3	5
Total consumer | Credit card
Financing Receivable [Line Items]
Subsequently default	7	16
Total consumer | Credit card | Repayment Plan
Financing Receivable [Line Items]
Subsequently default	$ 7	$ 16