Loans - Consumer, Excluding Credit Card Loan Portfolio, Other Consumer Impaired Loans and Loan Modifications (Details) - Consumer, excluding credit card - Other consumer - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
With an allowance	$ 207		$ 207		$ 222
Without an allowance	20		20		29
Total impaired loans	227		227		251
Allowance for loan losses related to impaired loans	68		68		63
Unpaid principal balance of impaired loans	327		327		355
Impaired loans on nonaccrual status	205		205		229
Average impaired loans	244	$ 277	245	$ 287
Loans modified in TDRs	72		72		79
TDRs on nonaccrual status	$ 50		$ 50		$ 57

Financing Receivable, Modifications, Recorded Investment, Nonaccrual Status

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- Definition

Impaired Financing Receivable, Recorded Investment, Nonaccrual Status

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No definition available.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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- Definition

The amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=82895541&loc=d3e18845-111554

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- Definition

Average 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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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Topic 310
-SubTopic 10
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-Paragraph 15
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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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Amount of allowance for credit losses related to recorded investment.

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Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses.

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Amount of investment in impaired financing receivables for which there is no related allowance for credit losses.

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Amount of investment in impaired financing receivables for which there is a related allowance for credit losses.

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