FINANCIAL INSTRUMENTS - Cash Flow Hedge Activity (Details) - Cash flow hedges - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Derivative [Line Items]
Gain (loss) recognized in AOCI	$ (162)	$ 34	$ 12	$ (20)	$ 56	$ (45)
Gain (loss) reclassified from AOCI into earnings	(72)	65	14	(7)	64	(71)
Interest rate contracts
Derivative [Line Items]
Gain (loss) recognized in AOCI	(3)	3	12	(7)	2	31
Gain (loss) reclassified from AOCI into earnings	(4)	(6)	(26)	(6)	(15)	(55)
Currency exchange contracts
Derivative [Line Items]
Gain (loss) recognized in AOCI	(158)	32	1	(13)	54	(77)
Gain (loss) reclassified from AOCI into earnings	(68)	71	40	(1)	79	(13)
Commodity contracts
Derivative [Line Items]
Gain (loss) recognized in AOCI	0	(2)	(1)	0	0	0
Gain (loss) reclassified from AOCI into earnings	$ 0	$ 0	$ (1)	$ 0	$ 0	$ (3)