STOCKHOLDERS' EQUITY STOCKHOLDERS' EQUITY - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ (8,988)	$ (9,387)	$ (8,988)	$ (9,387)		$ (9,885)
Other Comprehensive Income (Loss), Net of Tax	2	(242)	104	241
Transfer of Business Under Common Control			1,963	(215)
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Tax	(11)	3	(29)	8
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	49	(23)	49	(23)	$ 16	(51)	$ (8)	$ 17
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	41	(15)	109	(41)
Other Comprehensive Income (Loss), Net of Tax	33	(14)	100	(39)
Other Comprehensive Income (Loss), before Reclassifications, before Tax	52	(18)	138	(49)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Tax	15	(25)	14	(20)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	(1,067)	(1,682)	(1,067)	(1,682)	(1,844)	(1,813)	(1,105)		$ (1,481)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	91	(468)	78	(92)
Other Comprehensive Income (Loss), Net of Tax	67	(470)	36	(94)
Other Comprehensive Income (Loss), before Reclassifications, before Tax	76	(443)	64	(72)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Tax	(10)	0	(10)	0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	(7,635)	(7,675)	(7,635)	(7,675)	(7,824)	(7,965)	(6,872)		(6,998)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	24	0	24	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	82	124	223	250
Other Comprehensive Income (Loss), Net of Tax	106	124	247	250
Other Comprehensive Income (Loss), before Reclassifications, before Tax	34	0	34	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	108	158	274	312
Reclassification from AOCI, Current Period, Tax	(26)	(34)	(51)	(62)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Tax	46	(17)	73	(19)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	(335)	(7)	(335)	(7)	$ (131)	$ (56)	$ (103)		$ (109)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(217)	91	(285)	75
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	13	27	6	49
Other Comprehensive Income (Loss), Net of Tax	(204)	118	(279)	124
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(263)	108	(358)	94
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	17	32	10	59
Reclassification from AOCI, Current Period, Tax	(4)	(5)	(4)	(10)
Investment in nonconsolidated affiliates [Member] | Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax			45
Retained Earnings [Member] | Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	0	(1)	0	(1)
Retained Earnings [Member] | Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Transfer of Business Under Common Control	710	0	710	0
Cumulative Effect of New Accounting Principle in Period of Adoption	0	(107)	0	(107)
Retained Earnings [Member] | Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Transfer of Business Under Common Control	83	0	83	0
Cumulative Effect of New Accounting Principle in Period of Adoption	0	(927)	0	(927)
Retained Earnings [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	0	(22)	0	(22)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(8)	1	(9)	2
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	(11)	1	(12)	3
Reclassification from AOCI, Current Period, Tax	3	0	3	(1)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	$ (24)	$ (2)	$ (42)	$ (2)