Loans - 90+ Day Delinquent Loans Accruing Interest and Nonperforming Loans (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days Past Due and Accruing	$ 1,650	$ 1,936
Nonperforming Loans	$ 1,292	$ 1,599
Percent 90 days past due and still accruing	0.68%	0.79%
Financing Receivable, Nonaccrual, Percent Past Due	0.53%	0.65%
Credit Card Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days Past Due and Accruing	$ 1,650	$ 1,936
Nonperforming Loans	32	42
Credit Card Portfolio Segment [Member] \| Geographic Distribution, Domestic [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days Past Due and Accruing	1,542	1,840
Credit Card Portfolio Segment [Member] \| Geographic Distribution, Foreign [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days Past Due and Accruing	108	96
Nonperforming Loans	32	42
Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days Past Due and Accruing	0	0
Nonperforming Loans	$ 565	$ 527
Financing Receivable, Nonaccrual, Percent Past Due	0.75%	0.72%
Consumer Portfolio Segment [Member] \| Auto
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days Past Due and Accruing	$ 0	$ 0
Nonperforming Loans	$ 273	$ 223
Financing Receivable, Nonaccrual, Percent Past Due	0.53%	0.47%
Consumer Portfolio Segment [Member] \| Home loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days Past Due and Accruing	$ 0	$ 0
Nonperforming Loans	$ 259	$ 273
Financing Receivable, Nonaccrual, Percent Past Due	1.31%	1.26%
Consumer Portfolio Segment [Member] \| Retail banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days Past Due and Accruing	$ 0	$ 0
Nonperforming Loans	$ 33	$ 31
Financing Receivable, Nonaccrual, Percent Past Due	0.96%	0.86%
Commercial Banking
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days Past Due and Accruing	$ 0	$ 0
Nonperforming Loans	686	1,022
Commercial Banking \| Total commercial lending
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days Past Due and Accruing	0	0
Nonperforming Loans	677	1,018
Commercial Banking \| Commercial and multifamily real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days Past Due and Accruing	0	0
Nonperforming Loans	34	30
Commercial Banking \| Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days Past Due and Accruing	0	0
Nonperforming Loans	643	988
Commercial Banking \| Small-ticket commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days Past Due and Accruing	0	0
Nonperforming Loans	9	4
Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days Past Due and Accruing	0	0
Nonperforming Loans	$ 9	$ 8

Financing Receivable, Percent 90 Days Past Due and Still Accruing

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- Definition

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+ References

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- Definition

Recorded investment in financing receivables that are 90 days or more past due and still accruing.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Recorded Investment
-URI http://asc.fasb.org/extlink&oid=65880944

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5111-111524

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- Definition

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