Credit Quality (Recorded Investment in Impaired Loans and Related Allowance by Class) (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Impaired Financing Receivable Unpaid Principal Balance
Impaired Financing Receivable With Related Allowance Unpaid Principal Balance	$ 934	$ 846
Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance	492	536
Unpaid Principal Balance	1,426	1,382
Impaired Financing Receivable Recorded Investment Abstract
Impaired Financing Receivable With Related Allowance Recorded Investment	886	787
Impaired Financing Receivable With No Related Allowance Recorded Investment	466	504
Recorded investment	1,352	1,291
Allowance	160	141
Commercial Portfolio Segment \| Commercial and Industrial Loans
Impaired Financing Receivable Unpaid Principal Balance
Impaired Financing Receivable With Related Allowance Unpaid Principal Balance	246	156
Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance	84	137
Impaired Financing Receivable Recorded Investment Abstract
Impaired Financing Receivable With Related Allowance Recorded Investment	206	107
Impaired Financing Receivable With No Related Allowance Recorded Investment	77	125
Allowance	53	34
Commercial Portfolio Segment \| Commercial Mortgage Loans, Owner-occupied
Impaired Financing Receivable Unpaid Principal Balance
Impaired Financing Receivable With Related Allowance Unpaid Principal Balance	9	2
Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance	18	9
Impaired Financing Receivable Recorded Investment Abstract
Impaired Financing Receivable With Related Allowance Recorded Investment	9	2
Impaired Financing Receivable With No Related Allowance Recorded Investment	18	9
Allowance	1	1
Commercial Portfolio Segment \| Commercial Mortgage Loans, Nonowner-Occupied
Impaired Financing Receivable Unpaid Principal Balance
Impaired Financing Receivable With Related Allowance Unpaid Principal Balance	2	2
Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance	11	11
Impaired Financing Receivable Recorded Investment Abstract
Impaired Financing Receivable With Related Allowance Recorded Investment	1	1
Impaired Financing Receivable With No Related Allowance Recorded Investment	11	11
Allowance	0	0
Commercial Portfolio Segment \| Commercial Leases
Impaired Financing Receivable Unpaid Principal Balance
Impaired Financing Receivable With Related Allowance Unpaid Principal Balance	25	23
Impaired Financing Receivable Recorded Investment Abstract
Impaired Financing Receivable With Related Allowance Recorded Investment	24	22
Allowance	8	7
Residential Mortgage Loans
Impaired Financing Receivable Unpaid Principal Balance
Impaired Financing Receivable With Related Allowance Unpaid Principal Balance	457	465
Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance	297	292
Impaired Financing Receivable Recorded Investment Abstract
Impaired Financing Receivable With Related Allowance Recorded Investment	454	462
Impaired Financing Receivable With No Related Allowance Recorded Investment	280	274
Allowance	60	61
Consumer Portfolio Segment \| Home Equity
Impaired Financing Receivable Unpaid Principal Balance
Impaired Financing Receivable With Related Allowance Unpaid Principal Balance	144	146
Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance	80	85
Impaired Financing Receivable Recorded Investment Abstract
Impaired Financing Receivable With Related Allowance Recorded Investment	143	145
Impaired Financing Receivable With No Related Allowance Recorded Investment	79	83
Allowance	23	22
Consumer Portfolio Segment \| Indirect secured consumer loans
Impaired Financing Receivable Unpaid Principal Balance
Impaired Financing Receivable With Related Allowance Unpaid Principal Balance	5	5
Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance	2	2
Impaired Financing Receivable Recorded Investment Abstract
Impaired Financing Receivable With Related Allowance Recorded Investment	5	4
Impaired Financing Receivable With No Related Allowance Recorded Investment	1	2
Allowance	1	1
Consumer Portfolio Segment \| Credit Card
Impaired Financing Receivable Unpaid Principal Balance
Impaired Financing Receivable With Related Allowance Unpaid Principal Balance	46	47
Impaired Financing Receivable Recorded Investment Abstract
Impaired Financing Receivable With Related Allowance Recorded Investment	44	44
Allowance	$ 14	$ 15

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

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
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-Publisher FASB
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