ACCUMULATED OTHER COMPREHENSIVE LOSS Reclassification Out of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	$ 150	$ 65	$ 299	$ 151
Nonoperating Income (Expense)	5	322	88	(122)
Unrealized gains (losses) on investments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	1	(35)	3	(47)
Reclassification from AOCI, Current Period, Tax	0	13	(1)	17
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	1	(22)	2	(30)
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Nonoperating Income (Expense)	(2)	(6)	(2)	(6)
Pension and other postretirement benefit plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	158	149	312	298
Reclassification from AOCI, Current Period, Tax	(34)	(48)	(62)	(95)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	124	101	250	203
Derivative instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	32	(8)	59	(15)
Reclassification from AOCI, Current Period, Tax	(5)	0	(10)	(1)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	$ 27	$ (8)	$ 49	$ (16)