Credit Quality and the Allowance for Loan and Lease Losses - Summary of Loans Modified in a TDR (Details) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2022 USD ($) loan	Sep. 30, 2021 USD ($) loan	Sep. 30, 2022 USD ($) loan	Sep. 30, 2021 USD ($) loan
Financing Receivable, Modifications
Number of Loans Modified in a TDR During the Period \| loan	2,093	2,400	7,381	8,190
Amortized Cost Basis of Loans Modified in a TDR During the Period	$ 77	$ 67	$ 451	$ 262
Increase (Decrease) to ALLL Upon Modification	2	1	22	8
Charge-offs Recognized Upon Modification	$ 0	$ 0	$ 0	$ 0
Commercial \| Commercial and industrial loans
Financing Receivable, Modifications
Number of Loans Modified in a TDR During the Period \| loan	19	29	69	55
Amortized Cost Basis of Loans Modified in a TDR During the Period	$ 31	$ 23	$ 196	$ 54
Increase (Decrease) to ALLL Upon Modification	0	(1)	13	0
Charge-offs Recognized Upon Modification	$ 0	$ 0	$ 0	$ 0
Commercial \| Commercial mortgage owner-occupied loans
Financing Receivable, Modifications
Number of Loans Modified in a TDR During the Period \| loan	2	3	8	4
Amortized Cost Basis of Loans Modified in a TDR During the Period	$ 1	$ 1	$ 5	$ 6
Increase (Decrease) to ALLL Upon Modification	0	0	(1)	0
Charge-offs Recognized Upon Modification	$ 0	$ 0	$ 0	$ 0
Commercial \| Commercial mortgage nonowner-occupied loans
Financing Receivable, Modifications
Number of Loans Modified in a TDR During the Period \| loan		1	3	4
Amortized Cost Basis of Loans Modified in a TDR During the Period		$ 0	$ 23	$ 26
Increase (Decrease) to ALLL Upon Modification		0	0	0
Charge-offs Recognized Upon Modification		$ 0	$ 0	$ 0
Commercial \| Commercial construction loans
Financing Receivable, Modifications
Number of Loans Modified in a TDR During the Period \| loan			2
Amortized Cost Basis of Loans Modified in a TDR During the Period			$ 4
Increase (Decrease) to ALLL Upon Modification			(3)
Charge-offs Recognized Upon Modification			$ 0
Residential Mortgage
Financing Receivable, Modifications
Number of Loans Modified in a TDR During the Period \| loan	190	98	928	400
Amortized Cost Basis of Loans Modified in a TDR During the Period	$ 28	$ 15	$ 143	$ 74
Increase (Decrease) to ALLL Upon Modification	0	1	7	3
Charge-offs Recognized Upon Modification	$ 0	$ 0	$ 0	$ 0
Consumer \| Home equity
Financing Receivable, Modifications
Number of Loans Modified in a TDR During the Period \| loan	54	54	178	151
Amortized Cost Basis of Loans Modified in a TDR During the Period	$ 3	$ 3	$ 13	$ 8
Increase (Decrease) to ALLL Upon Modification	(1)	(1)	(3)	(2)
Charge-offs Recognized Upon Modification	$ 0	$ 0	$ 0	$ 0
Consumer \| Indirect secured consumer loans
Financing Receivable, Modifications
Number of Loans Modified in a TDR During the Period \| loan	448	1,045	2,499	3,238
Amortized Cost Basis of Loans Modified in a TDR During the Period	$ 7	$ 19	$ 48	$ 70
Increase (Decrease) to ALLL Upon Modification	0	0	1	1
Charge-offs Recognized Upon Modification	$ 0	$ 0	$ 0	$ 0
Consumer \| Credit card
Financing Receivable, Modifications
Number of Loans Modified in a TDR During the Period \| loan	1,380	1,170	3,694	4,338
Amortized Cost Basis of Loans Modified in a TDR During the Period	$ 7	$ 6	$ 19	$ 24
Increase (Decrease) to ALLL Upon Modification	3	2	8	6
Charge-offs Recognized Upon Modification	$ 0	$ 0	$ 0	$ 0

Amount of credit loss expense (reversal of expense) on financing receivable from change in methodology. Excludes net investment in lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 11
-Subparagraph (e)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919244-210447

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
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