Allowance for Credit Losses - Gross Charge-Offs by Year of Origination (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Allowance for Loan and Lease Losses [Roll Forward]
Year one, current fiscal year charge offs	$ 9	$ 13
Year two, current fiscal year charge offs	18	19
Year three, current fiscal year charge offs	21	82
Year four, current fiscal year charge offs	23	5
Year five, current fiscal year charge offs	20	12
Prior year charge offs	53	54
Revolving loans charge offs	13	14
Total charge offs	157	199	$ 93
Commercial \| Commercial, financial and industrial
Allowance for Loan and Lease Losses [Roll Forward]
Year one, current fiscal year charge offs	1	1
Year two, current fiscal year charge offs	16	17
Year three, current fiscal year charge offs	15	82
Year four, current fiscal year charge offs	23	5
Year five, current fiscal year charge offs	3	10
Prior year charge offs	15	34
Revolving loans charge offs	4	7
Total charge offs	77	156	62
Commercial \| Commercial Real Estate
Allowance for Loan and Lease Losses [Roll Forward]
Year one, current fiscal year charge offs	0	0
Year two, current fiscal year charge offs	0	0
Year three, current fiscal year charge offs	5	0
Year four, current fiscal year charge offs	0	0
Year five, current fiscal year charge offs	17	2
Prior year charge offs	34	15
Revolving loans charge offs	0	0
Total charge offs	56	17	1
Consumer \| Consumer real estate
Allowance for Loan and Lease Losses [Roll Forward]
Year one, current fiscal year charge offs	0	0
Year two, current fiscal year charge offs	1	1
Year three, current fiscal year charge offs	0	0
Year four, current fiscal year charge offs	0	0
Year five, current fiscal year charge offs	0	0
Prior year charge offs	2	3
Revolving loans charge offs	0	0
Total charge offs	3	4	5
Consumer \| Credit card and other
Allowance for Loan and Lease Losses [Roll Forward]
Year one, current fiscal year charge offs	8	12
Year two, current fiscal year charge offs	1	1
Year three, current fiscal year charge offs	1	0
Year four, current fiscal year charge offs	0	0
Year five, current fiscal year charge offs	0	0
Prior year charge offs	2	2
Revolving loans charge offs	9	7
Total charge offs	$ 21	$ 22	$ 25

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

No definition available.

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- Definition

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

+ References

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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- Definition

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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- Definition

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

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