Credit Quality (Summary of Average Impaired Loans and Leases and Interest Income by Class) (Detail) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Financing Receivable, Impaired
Average Recorded Investment	$ 1,321	$ 1,539
Interest Income Recognized	14	15
Commercial Portfolio Segment \| Commercial and Industrial Loans
Financing Receivable, Impaired
Average Recorded Investment	258	497
Interest Income Recognized	2	5
Commercial Portfolio Segment \| Commercial Mortgage Loans, Owner-occupied
Financing Receivable, Impaired
Average Recorded Investment	19	22
Interest Income Recognized	0	0
Commercial Portfolio Segment \| Commercial Mortgage Loans, Nonowner-Occupied
Financing Receivable, Impaired
Average Recorded Investment	13	34
Interest Income Recognized	0	0
Commercial Portfolio Segment \| Commercial Leases
Financing Receivable, Impaired
Average Recorded Investment	23	6
Interest Income Recognized	1	0
Residential Mortgage Loans
Financing Receivable, Impaired
Average Recorded Investment	734	665
Interest Income Recognized	7	6
Consumer Portfolio Segment \| Home Equity
Financing Receivable, Impaired
Average Recorded Investment	224	258
Interest Income Recognized	3	3
Consumer Portfolio Segment \| Indirect secured consumer loans
Financing Receivable, Impaired
Average Recorded Investment	6	9
Interest Income Recognized	0	0
Consumer Portfolio Segment \| Credit Card
Financing Receivable, Impaired
Average Recorded Investment	44	48
Interest Income Recognized	$ 1	$ 1

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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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