QUARTERLY FINANCIAL INFORMATION (UNAUDITED) (Quarterly Disclosures) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 3,911	$ 3,153	$ 3,546	$ 3,792	$ 3,684	$ 4,908	$ 5,168	$ 4,868	$ 14,402	$ 18,628	$ 16,403
Operating income (loss)	775	(38)	33	321	316	1,315	1,664	1,459	1,091	4,754	3,690
Net (loss) income from continuing operations	42	(235)	(74)	75	374	668	1,039	828	(192)	2,909	2,029
Net income (loss) from discontinued operations	1	1	0	1	4	(4)	(4)	(11)	3	(15)	66
Net income (loss)	43	(234)	(74)	76	378	664	1,035	817	(189)	2,894	2,095
Net (income) loss attributable to noncontrolling interests	(34)	27	2	(45)	107	(108)	(166)	(125)	(50)	(292)	(278)
Net (loss) income attributable to common stockholders	$ 9	$ (207)	$ (72)	$ 31	$ 485	$ 556	$ 869	$ 692	$ (239)	$ 2,602	$ 1,817
Continuing operations (in dollars per share)					$ 0.33	$ 0.38	$ 0.60	$ 0.48	$ (0.17)	$ 1.80	$ 1.21
Discontinued operations (in dollars per share)					0	0	0	(0.01)		(0.01)
Earnings per share, basic (in dollars per share)	$ 0	$ (0.15)	$ (0.05)	$ 0.02	0.33	0.38	0.60	0.47	(0.17)	1.79	1.25
Continuing operations (in dollars per share)					0.33	0.38	0.59	0.48	(0.17)	1.79	1.21
Discontinued operations (in dollars per share)					0	0	0	(0.01)	0	(0.01)	0.04
Earnings per share, diluted (in dollars per share)	$ 0	$ (0.15)	$ (0.05)	$ 0.02	$ 0.33	$ 0.38	$ 0.59	$ 0.47	$ (0.17)	$ 1.78	$ 1.25
Basic (in shares)	1,452,000,000	1,452,000,000	1,451,000,000	1,451,000,000	1,450,000,000	1,450,000,000	1,449,000,000	1,449,000,000	1,451,000,000	1,449,000,000	1,447,000,000
Diluted (in shares)	1,457,000,000	1,452,000,000	1,451,000,000	1,457,000,000	1,457,000,000	1,458,000,000	1,458,000,000	1,458,000,000	1,451,000,000	1,458,000,000	1,454,000,000