DERIVATIVES ACTIVITIES - Cash Flow Hedges (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Pretax change in accumulated other comprehensive income (loss)
Cash flow hedges expected to be reclassified within 12 months			$ (277)
Maximum length of time hedged in cash flow hedge			10 years
Cash flow hedging
Pretax change in accumulated other comprehensive income (loss)
Effective portion of cash flow hedges included in AOCI	$ (43)	$ (216)	$ 96	$ 422
Effective portion of cash flow hedges reclassified from AOCI to earnings	(55)	(85)	(102)	(185)
Interest rate contracts \| Cash flow hedging
Pretax change in accumulated other comprehensive income (loss)
Effective portion of cash flow hedges included in AOCI	(36)	(187)	103	448
Effective portion of cash flow hedges reclassified from AOCI to earnings	(48)	(39)	(94)	(96)
Foreign exchange contracts \| Cash flow hedging
Pretax change in accumulated other comprehensive income (loss)
Effective portion of cash flow hedges included in AOCI	(7)	(29)	(7)	(26)
Effective portion of cash flow hedges reclassified from AOCI to earnings	$ (7)	$ (46)	$ (8)	$ (89)

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994

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- Definition

The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4D
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624177-113959

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- Definition

The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

+ References

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- Definition

Maximum length of time over which the entity is hedging its exposure to the variability in future cash flows for forecasted transactions, excluding those forecasted transactions related to the payment of variable interest on existing financial instruments, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994

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- References

No definition available.

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