Credit Quality and the Allowance for Loan and Lease Losses - Summary of Loans Modified in a TDR (Details) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2022 USD ($) loan	Jun. 30, 2021 USD ($) loan	Jun. 30, 2022 USD ($) loan	Jun. 30, 2021 USD ($) loan
Financing Receivable, Modifications
Number of Loans Modified in a TDR During the Period \| loan	2,546	1,993	5,288	5,790
Amortized Cost Basis of Loans Modified in a TDR During the Period	$ 197	$ 66	$ 374	$ 193
Financing Receivable, Change in Method, Credit Loss Expense (Reversal)	4	2	20	7
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	20	7	50	26
Amortized Cost Basis of Loans Modified in a TDR During the Period	$ 74	$ 25	$ 165	$ 31
Financing Receivable, Change in Method, Credit Loss Expense (Reversal)	0	0	13	1
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	1		6	1
Amortized Cost Basis of Loans Modified in a TDR During the Period	$ 0		$ 4	$ 4
Financing Receivable, Change in Method, Credit Loss Expense (Reversal)	0		(1)	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 Period \| loan	3		3	3
Amortized Cost Basis of Loans Modified in a TDR During the Period	$ 23		$ 23	$ 25
Financing Receivable, Change in Method, Credit Loss Expense (Reversal)	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		2
Amortized Cost Basis of Loans Modified in a TDR During the Period	$ 4		$ 4
Financing Receivable, Change in Method, Credit Loss Expense (Reversal)	(3)		(3)
Charge-offs Recognized Upon Modification	$ 0		$ 0
Residential Mortgage
Financing Receivable, Modifications
Number of Loans Modified in a TDR During the Period \| loan	478	124	738	302
Amortized Cost Basis of Loans Modified in a TDR During the Period	$ 73	$ 23	$ 115	$ 59
Financing Receivable, Change in Method, Credit Loss Expense (Reversal)	4	1	7	2
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	72	39	124	97
Amortized Cost Basis of Loans Modified in a TDR During the Period	$ 3	$ 2	$ 10	$ 5
Financing Receivable, Change in Method, Credit Loss Expense (Reversal)	(1)	0	(2)	(1)
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	777	450	2,051	2,193
Amortized Cost Basis of Loans Modified in a TDR During the Period	$ 14	$ 8	$ 41	$ 51
Financing Receivable, Change in Method, Credit Loss Expense (Reversal)	1	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	1,193	1,373	2,314	3,168
Amortized Cost Basis of Loans Modified in a TDR During the Period	$ 6	$ 8	$ 12	$ 18
Financing Receivable, Change in Method, Credit Loss Expense (Reversal)	3	1	5	4
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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