Credit Quality and the Allowance for Loan and Lease Losses - Summary of Gross Charge-Offs Within the Commercial Portfolio Segments, by Class and Vintage (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Financing Receivable, Modifications
Total	$ 146	$ 110
Commercial
Financing Receivable, Modifications
Year One	0	0
Year Two	1	1
Year Three	2	11
Year Four	0	0
Year Five	0	0
Prior	0	0
Revolving Loans	37	21
Total	40	33
Commercial \| Commercial and industrial loans
Financing Receivable, Modifications
Year One	0	0
Year Two	1	1
Year Three	2	11
Year Four	0	0
Year Five	0	0
Prior	0	0
Revolving Loans	37	20
Total	40	32
Commercial \| Commercial construction loans
Financing Receivable, Modifications
Year One	0	0
Year Two	0	0
Year Three	0	0
Year Four	0	0
Year Five	0	0
Prior	0	0
Revolving Loans	0	1
Total	$ 0	$ 1

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
-SubTopic 20
-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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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
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 79
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479294/326-20-55-79

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