FAIR VALUE ELECTIONS - Certain Structured and Non-Structured Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Carrying value of structured notes, disaggregated by type of embedded derivative instrument
Carrying value of structured notes	$ 34,000	$ 29,300
Long-term debt
Certain non-structured liabilities
Aggregate unpaid principal balance in excess of (less than) fair value	1,967	(579)
Long-term debt \| Carrying amount
Certain non-structured liabilities
Carrying amount reported on the Consolidated Balance Sheet	36,772	31,392
Short-term borrowings
Certain non-structured liabilities
Aggregate unpaid principal balance in excess of fair value	781	74
Short-term borrowings \| Carrying amount
Certain non-structured liabilities
Carrying amount reported on the Consolidated Balance Sheet	5,042	4,627
Interest rate linked
Carrying value of structured notes, disaggregated by type of embedded derivative instrument
Carrying value of structured notes	16,800	13,900
Foreign exchange linked
Carrying value of structured notes, disaggregated by type of embedded derivative instrument
Carrying value of structured notes	400	300
Equity linked
Carrying value of structured notes, disaggregated by type of embedded derivative instrument
Carrying value of structured notes	15,200	13,000
Commodity linked
Carrying value of structured notes, disaggregated by type of embedded derivative instrument
Carrying value of structured notes	200	200
Credit linked
Carrying value of structured notes, disaggregated by type of embedded derivative instrument
Carrying value of structured notes	$ 1,400	$ 1,900

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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