Credit Quality and the Allowance for Loan and Lease Losses - Summary of Loans Modified in a TDR (Details) $ in Millions	12 Months Ended
Dec. 31, 2021 USD ($) loan	Dec. 31, 2020 USD ($) loan	Dec. 31, 2019 USD ($) loan
Financing Receivable, Modifications
Number of Loans Modified in a TDR During the Year \| loan	10,882	6,531	7,056
Recorded Investment in Loans Modified in a TDR During the Year	$ 450	$ 525	$ 374
(Decrease) Increase to ALLL Upon Modification	12	22	(10)
Charge-offs Recognized Upon Modification	$ 1	$ 8	$ 8
Commercial \| Commercial and industrial loans
Financing Receivable, Modifications
Number of Loans Modified in a TDR During the Year \| loan	86	124	97
Recorded Investment in Loans Modified in a TDR During the Year	$ 150	$ 305	$ 223
(Decrease) Increase to ALLL Upon Modification	1	26	(19)
Charge-offs Recognized Upon Modification	$ 0	$ 7	$ 5
Commercial \| Commercial mortgage owner-occupied loans
Financing Receivable, Modifications
Number of Loans Modified in a TDR During the Year \| loan	10	43	15
Recorded Investment in Loans Modified in a TDR During the Year	$ 8	$ 58	$ 12
(Decrease) Increase to ALLL Upon Modification	0	(11)	0
Charge-offs Recognized Upon Modification	$ 0	$ 0	$ 0
Commercial \| Commercial mortgage nonowner-occupied loans
Financing Receivable, Modifications
Number of Loans Modified in a TDR During the Year \| loan	5	19	1
Recorded Investment in Loans Modified in a TDR During the Year	$ 29	$ 44	$ 0
(Decrease) Increase to ALLL Upon Modification	0	(2)	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 Year \| loan	1	3
Recorded Investment in Loans Modified in a TDR During the Year	$ 34	$ 21
(Decrease) Increase to ALLL Upon Modification	0	1
Charge-offs Recognized Upon Modification	$ 0	$ 0
Residential Mortgage
Financing Receivable, Modifications
Number of Loans Modified in a TDR During the Year \| loan	519	424	722
Recorded Investment in Loans Modified in a TDR During the Year	$ 93	$ 58	$ 101
(Decrease) Increase to ALLL Upon Modification	4	1	1
Charge-offs Recognized Upon Modification	$ 0	$ 0	$ 0
Consumer \| Home equity
Financing Receivable, Modifications
Number of Loans Modified in a TDR During the Year \| loan	206	147	80
Recorded Investment in Loans Modified in a TDR During the Year	$ 10	$ 7	$ 4
(Decrease) Increase to ALLL Upon Modification	(3)	(4)	0
Charge-offs Recognized Upon Modification	$ 0	$ 0	$ 0
Consumer \| Indirect secured consumer loans
Financing Receivable, Modifications
Number of Loans Modified in a TDR During the Year \| loan	4,567	70	100
Recorded Investment in Loans Modified in a TDR During the Year	$ 96	$ 0	$ 0
(Decrease) Increase to ALLL Upon Modification	1	0	0
Charge-offs Recognized Upon Modification	$ 0	$ 0	$ 0
Consumer \| Credit card
Financing Receivable, Modifications
Number of Loans Modified in a TDR During the Year \| loan	5,488	5,701	6,041
Recorded Investment in Loans Modified in a TDR During the Year	$ 30	$ 32	$ 34
(Decrease) Increase to ALLL Upon Modification	9	11	8
Charge-offs Recognized Upon Modification	$ 1	$ 1	$ 3

Amount of credit loss expense (reversal of expense) for financing receivable from change in methodology.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 11
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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
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