Credit Quality - Recorded Investment in Impaired Loans and Related Allowance by Class (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Impaired Financing Receivable Unpaid Principal Balance
Impaired Financing Receivable With Related Allowance Unpaid Principal Balance	$ 929	$ 846
Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance	558	536
Unpaid Principal Balance	1,487	1,382
Impaired Financing Receivable Recorded Investment Abstract
Impaired Financing Receivable With Related Allowance Recorded Investment	841	787
Impaired Financing Receivable With No Related Allowance Recorded Investment	530	504
Recorded investment	1,371	1,291
Allowance	147	141
Commercial Portfolio Segment \| Commercial and Industrial Loans
Impaired Financing Receivable Unpaid Principal Balance
Impaired Financing Receivable With Related Allowance Unpaid Principal Balance	257	156
Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance	129	137
Impaired Financing Receivable Recorded Investment Abstract
Impaired Financing Receivable With Related Allowance Recorded Investment	178	107
Impaired Financing Receivable With No Related Allowance Recorded Investment	121	125
Allowance	44	34
Commercial Portfolio Segment \| Commercial Mortgage Loans, Owner-occupied
Impaired Financing Receivable Unpaid Principal Balance
Impaired Financing Receivable With Related Allowance Unpaid Principal Balance	5	2
Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance	21	9
Impaired Financing Receivable Recorded Investment Abstract
Impaired Financing Receivable With Related Allowance Recorded Investment	5	2
Impaired Financing Receivable With No Related Allowance Recorded Investment	20	9
Allowance	0	1
Commercial Portfolio Segment \| Commercial Mortgage Loans, Nonowner-Occupied
Impaired Financing Receivable Unpaid Principal Balance
Impaired Financing Receivable With Related Allowance Unpaid Principal Balance	1	2
Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance	3	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	3	11
Allowance	0	0
Commercial Portfolio Segment \| Commercial Leases
Impaired Financing Receivable Unpaid Principal Balance
Impaired Financing Receivable With Related Allowance Unpaid Principal Balance	31	23
Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance	3
Impaired Financing Receivable Recorded Investment Abstract
Impaired Financing Receivable With Related Allowance Recorded Investment	27	22
Impaired Financing Receivable With No Related Allowance Recorded Investment	3
Allowance	9	7
Residential Mortgage Loans
Impaired Financing Receivable Unpaid Principal Balance
Impaired Financing Receivable With Related Allowance Unpaid Principal Balance	451	465
Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance	328	292
Impaired Financing Receivable Recorded Investment Abstract
Impaired Financing Receivable With Related Allowance Recorded Investment	448	462
Impaired Financing Receivable With No Related Allowance Recorded Investment	310	274
Allowance	58	61
Consumer Portfolio Segment \| Home Equity
Impaired Financing Receivable Unpaid Principal Balance
Impaired Financing Receivable With Related Allowance Unpaid Principal Balance	134	146
Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance	73	85
Impaired Financing Receivable Recorded Investment Abstract
Impaired Financing Receivable With Related Allowance Recorded Investment	134	145
Impaired Financing Receivable With No Related Allowance Recorded Investment	72	83
Allowance	22	22
Consumer Portfolio Segment \| Indirect secured consumer loans
Impaired Financing Receivable Unpaid Principal Balance
Impaired Financing Receivable With Related Allowance Unpaid Principal Balance	4	5
Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance	1	2
Impaired Financing Receivable Recorded Investment Abstract
Impaired Financing Receivable With Related Allowance Recorded Investment	4	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	$ 13	$ 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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-Name Accounting Standards Codification
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