Credit Quality - Summary of Average Impaired Loans and Leases and Interest Income by Class (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	$ 1,394	$ 1,581	$ 1,356	$ 1,546
Interest Income Recognized	13	17	28	32
Commercial Portfolio Segment \| Commercial and Industrial Loans
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	322	417	292	439
Interest Income Recognized	2	5	4	10
Commercial Portfolio Segment \| Commercial Mortgage Loans, Owner-occupied
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	27	16	21	20
Interest Income Recognized	0	0	0	0
Commercial Portfolio Segment \| Commercial Mortgage Loans, Nonowner-Occupied
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	9	29	10	32
Interest Income Recognized	0	0	0	0
Commercial Portfolio Segment \| Commercial Leases
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	30	18	27	14
Interest Income Recognized	0	0	1	0
Residential Mortgage Loans
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	740	799	737	732
Interest Income Recognized	7	8	15	14
Consumer Portfolio Segment \| Home Equity
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	217	248	220	253
Interest Income Recognized	3	3	6	6
Consumer Portfolio Segment \| Indirect secured consumer loans
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	6	8	6	9
Interest Income Recognized	0	0	0	0
Consumer Portfolio Segment \| Credit Card
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	43	46	43	47
Interest Income Recognized	$ 1	$ 1	$ 2	$ 2

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Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5258-111524

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Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

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