Loans and Related Allowance for Credit Losses, Allowance for Credit Losses for Loans Activity by Portfolio Segment (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses, beginning balance	$ 13,788	$ 19,713
Provision for credit losses	(775)	(1,117)
Interest income on certain loans	(29)	(41)
Loan charge-offs	(647)	(879)
Loan recoveries	342	366
Net loan charge-offs	(305)	(513)
Other	2	1
Allowance for credit losses, ending balance	12,681	18,043
Total Commercial [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses, beginning balance	7,791	11,516
Provision for credit losses	(665)	(667)
Interest income on certain loans	(9)	(19)
Loan charge-offs	(60)	(232)
Loan recoveries	89	83
Net loan charge-offs	29	(149)
Other	2	1
Allowance for credit losses, ending balance	7,148	10,682
Total Consumer [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses, beginning balance	5,997	8,197
Provision for credit losses	(110)	(450)
Interest income on certain loans	(20)	(22)
Loan charge-offs	(587)	(647)
Loan recoveries	253	283
Net loan charge-offs	(334)	(364)
Other	0	0
Allowance for credit losses, ending balance	$ 5,533	$ 7,361

Amount of other addition (reduction) in allowance reserve for credit loss.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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Amount, after recoveries, of loans and leases that have been written-off.

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Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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The amount of interest income on impaired and nonperforming loans that is due to the change in present value attributable to the passage of time.

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Amount of expense related to estimated loss from loan and lease transactions.

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Amount of increase in valuation and qualifying accounts and reserves from recovery of amount previously written off or reestablishment of reserve previously utilized.

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