FAIR VALUE ELECTIONS - Certain Structured and Non-Structured Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Carrying value of structured notes, disaggregated by type of embedded derivative instrument
Carrying value of structured notes	$ 31,300	$ 29,300
Long-term debt
Certain non-structured liabilities
Aggregate unpaid principal balance in excess of (less than) fair value, long-term	(93)	(579)
Long-term debt \| Carrying amount
Certain non-structured liabilities
Carrying amount reported on the Consolidated Balance Sheet	33,571	31,392
Short-term borrowings
Certain non-structured liabilities
Aggregate unpaid principal balance in excess of (less than) fair value, short-term	463	74
Short-term borrowings \| Carrying amount
Certain non-structured liabilities
Carrying amount reported on the Consolidated Balance Sheet	4,467	4,627
Interest rate linked
Carrying value of structured notes, disaggregated by type of embedded derivative instrument
Carrying value of structured notes	15,900	13,900
Foreign exchange linked
Carrying value of structured notes, disaggregated by type of embedded derivative instrument
Carrying value of structured notes	300	300
Equity linked
Carrying value of structured notes, disaggregated by type of embedded derivative instrument
Carrying value of structured notes	12,800	13,000
Commodity linked
Carrying value of structured notes, disaggregated by type of embedded derivative instrument
Carrying value of structured notes	400	200
Credit linked
Carrying value of structured notes, disaggregated by type of embedded derivative instrument
Carrying value of structured notes	$ 1,900	$ 1,900

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+ References

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This item represents the difference between the aggregate fair value and the aggregate unpaid principal balance of long-term debt instruments that have contractual principal amounts and for which the fair value option has been elected.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-Subparagraph (d)(2)
-URI http://asc.fasb.org/extlink&oid=75031198&loc=d3e14064-108612

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Fair value of financial and nonfinancial obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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