Variable Interest Entities and Securitization Activities (Proceeds from retained interests in securitization transactions) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2013
Securitization Activities and Variable Interest Entities [Abstract]
Proceeds received from new securitization transactions	$ 2,713	$ 4,891
Proceeds from retained interests in securitization transactions	631	948
Collateralized Loan Obligations \| Special Purpose Entities
Variable Interest Entity
Maturities, payments and sales	$ 31	$ 345	$ 2,347

No definition available.

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- Definition

Cash Flows between a transferor and a transferee attributable to newly transferred assets related to either a securitization, asset-backed financing arrangement, or similar transfer in which the transferor has continuing involvement with the transferred financial assets underlying the transaction (including, but not limited to, servicing, recourse, and restrictions on transferor's interests in the transferred financial assets).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (d)(1)
-URI http://asc.fasb.org/extlink&oid=51814546&loc=d3e107207-111719

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- Definition

The cash inflow from the collection of a retained interest in a receivable securitized via a structured process whereby interests in loans and other receivables are packaged, underwritten, and sold in the form of asset-backed securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3179-108585

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- Definition

The cash inflow associated with the sale of loans receivables arising from the financing of goods and services.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3179-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

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- Definition

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.

+ References

No definition available.

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