FAIR VALUE ELECTIONS - Certain Structured and Non-Structured Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Carrying value of structured notes, disaggregated by type of embedded derivative instrument
Carrying value of structured notes	$ 40,800	$ 35,700
Long-term debt
Certain non-structured liabilities
Aggregate unpaid principal balance in excess of (less than) fair value	2,610	3,814
Long-term debt \| Carrying amount
Certain non-structured liabilities
Carrying amount reported on the Consolidated Balance Sheet	44,088	38,229
Short-term borrowings
Certain non-structured liabilities
Aggregate unpaid principal balance in excess of fair value	631	861
Short-term borrowings \| Carrying amount
Certain non-structured liabilities
Carrying amount reported on the Consolidated Balance Sheet	5,172	4,483
Interest rate linked
Carrying value of structured notes, disaggregated by type of embedded derivative instrument
Carrying value of structured notes	18,700	17,300
Foreign exchange linked
Carrying value of structured notes, disaggregated by type of embedded derivative instrument
Carrying value of structured notes	1,000	500
Equity linked
Carrying value of structured notes, disaggregated by type of embedded derivative instrument
Carrying value of structured notes	17,900	14,800
Commodity linked
Carrying value of structured notes, disaggregated by type of embedded derivative instrument
Carrying value of structured notes	1,200	1,200
Credit linked
Carrying value of structured notes, disaggregated by type of embedded derivative instrument
Carrying value of structured notes	$ 2,000	$ 1,900

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Fair value of financial and nonfinancial obligations.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
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-Section 50
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