STOCKHOLDERS' EQUITY (Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (9,885)	$ (8,591)		$ (8,571)
Accumulated Other Comprehensive Loss
Beginning balance	27,009	27,229	$ 26,183
Other comprehensive income (loss) before reclassifications	(786)	911	(1,882)
Amounts reclassified from accumulated other comprehensive income (loss)	529	320	727
Net other comprehensive income (loss)	(257)	1,231	(1,155)
Reclassification of stranded tax effects	(1,057)
Ending balance	27,969	27,009	27,229
Total Accum Other Comp Loss
Accumulated Other Comprehensive Loss
Beginning balance	(8,591)	(9,822)	(8,667)
Balance at Jan 1, 2018		(8,571)
Net other comprehensive income (loss)	(257)	1,231	(1,155)
Ending balance	(9,885)	(8,591)	(9,822)
Unrealized Gains (Losses) on Investments
Accumulated Other Comprehensive Loss
Beginning balance	(3)	43	47
Balance at Jan 1, 2018		17
Other comprehensive income (loss) before reclassifications	(74)	25	32
Amounts reclassified from accumulated other comprehensive income (loss)	7	(71)	(36)
Net other comprehensive income (loss)	(67)	(46)	(4)
Reclassification of stranded tax effects	(1)
Ending balance	(51)	(3)	43
Cumulative Translation Adj
Accumulated Other Comprehensive Loss
Beginning balance	(1,481)	(2,381)	(1,737)
Balance at Jan 1, 2018		(1,481)
Other comprehensive income (loss) before reclassifications	(221)	908	(644)
Amounts reclassified from accumulated other comprehensive income (loss)	(4)	(8)	0
Net other comprehensive income (loss)	(225)	900	(644)
Reclassification of stranded tax effects	(107)
Ending balance	(1,813)	(1,481)	(2,381)
Pension and Other Postretire Benefits
Accumulated Other Comprehensive Loss
Beginning balance	(6,998)	(7,389)	(6,769)
Balance at Jan 1, 2018		(6,998)
Other comprehensive income (loss) before reclassifications	(495)	(23)	(1,354)
Amounts reclassified from accumulated other comprehensive income (loss)	455	414	734
Net other comprehensive income (loss)	(40)	391	(620)
Reclassification of stranded tax effects	(927)
Ending balance	(7,965)	(6,998)	(7,389)
Derivative Instruments
Accumulated Other Comprehensive Loss
Beginning balance	(109)	(95)	(208)
Balance at Jan 1, 2018		(109)
Other comprehensive income (loss) before reclassifications	4	1	84
Amounts reclassified from accumulated other comprehensive income (loss)	71	(15)	29
Net other comprehensive income (loss)	75	(14)	113
Reclassification of stranded tax effects	(22)
Ending balance	$ (56)	$ (109)	$ (95)
Accounting Standards Update 2016-01 [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax				$ 20