Loans - By Portfolio Segment (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Loans and Leases Receivable Disclosure [Line Items]
Retained	$ 924,838	$ 889,907	$ 832,792
Held-for-sale	3,351	2,628
At fair value	2,508	2,230
Total	930,697	894,765
Consumer, excluding credit card
Loans and Leases Receivable Disclosure [Line Items]
Retained	372,553	364,406	344,355
Held-for-sale	128	238
At fair value	0	0
Total	372,681	364,644
Credit card
Loans and Leases Receivable Disclosure [Line Items]
Retained	149,387	141,711
Held-for-sale	124	105
At fair value	0	0
Total	149,511	141,816
Wholesale
Loans and Leases Receivable Disclosure [Line Items]
Retained	402,898	383,790	$ 357,050
Held-for-sale	3,099	2,285
At fair value	2,508	2,230
Total	$ 408,505	$ 388,305

Loans Receivable, Net of Deferred Income

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+ References

No definition available.

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- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5074-111524

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- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2196772

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Amount, after allowance for bad debt, of loan receivables held-for-sale that are not part of a disposal group. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities.

+ References

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