Credit Quality and the Allowance for Loan and Lease Losses - Summary of Gross Charge-Offs Within the Residential Mortgage and Consumer Portfolio Segments, by Class and Vintage (Details) $ in Millions	6 Months Ended
Jun. 30, 2023 USD ($)
Residential Mortgage
Financing Receivable, Modifications
Year One	$ 0
Year Two	0
Year Three	0
Year Four	0
Year Five	0
Prior	2
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	2
Consumer \| Home equity
Financing Receivable, Modifications
Year One	0
Year Two	0
Year Three	0
Year Four	0
Year Five	0
Prior	1
Revolving Loans	3
Revolving Loans Converted to Term Loans	0
Total	4
Consumer \| Indirect secured consumer loans
Financing Receivable, Modifications
Year One	1
Year Two	18
Year Three	12
Year Four	7
Year Five	5
Prior	5
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	48
Consumer \| Credit card
Financing Receivable, Modifications
Year One	0
Year Two	0
Year Three	0
Year Four	0
Year Five	0
Prior	0
Revolving Loans	40
Revolving Loans Converted to Term Loans	0
Total	40
Consumer \| Other consumer loans
Financing Receivable, Modifications
Year One	0
Year Two	25
Year Three	10
Year Four	6
Year Five	4
Prior	6
Revolving Loans	16
Revolving Loans Converted to Term Loans	1
Total	68
Consumer and residential mortgage loans
Financing Receivable, Modifications
Year One	1
Year Two	43
Year Three	22
Year Four	13
Year Five	9
Prior	14
Revolving Loans	59
Revolving Loans Converted to Term Loans	1
Total	$ 162

Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-6

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
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-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-13

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Amount, excluding accrued interest, of writeoff of financing receivable originated more than five years before current fiscal year. Excludes net investment in lease.

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Amount, excluding accrued interest, of writeoff of revolving financing receivable converted to term loan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-6A

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Amount, excluding accrued interest, of writeoff of financing receivable originated four years before current fiscal year. Excludes net investment in lease.

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Amount, excluding accrued interest, of writeoff of financing receivable originated three years before current fiscal year. Excludes net investment in lease.

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Amount, excluding accrued interest, of writeoff of financing receivable originated in current fiscal year. Excludes net investment in lease.

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Amount, excluding accrued interest, of writeoff of financing receivable originated two years before current fiscal year. Excludes net investment in lease.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-5

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
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-Name Accounting Standards Codification
-Section 55
-Paragraph 79
-Publisher FASB
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