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	9 Months Ended
Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Financing Receivable, Modifications
Total	$ 183	$ 158	$ 511	$ 389
Commercial
Financing Receivable, Modifications
Year One			1	24
Year Two			2	6
Year Three			15	12
Year Four			1	1
Year Five			1	0
Prior			0	5
Revolving Loans			183	92
Total	$ 80	$ 70	203	140
Commercial \| Commercial and industrial loans
Financing Receivable, Modifications
Year One			1	24
Year Two			2	6
Year Three			15	12
Year Four			1	1
Year Five			1	0
Prior			0	5
Revolving Loans			183	90
Total			203	138
Commercial \| Commercial mortgage owner-occupied 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
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
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-URI https://asc.fasb.org/1943274/2147479319/326-20-50-6

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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