QUARTERLY FINANCIAL INFORMATION (UNAUDITED) (Quarterly Disclosures) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 3,684	$ 4,908	$ 5,168	$ 4,868	$ 5,041	$ 4,310	$ 3,711	$ 3,341	$ 18,628	$ 16,403	$ 14,830
Operating income (loss)	316	1,315	1,664	1,459	1,479	928	686	597	4,754	3,690	(2,729)
Net (loss) income from continuing operations	374	668	1,039	828	1,193	242	326	268	2,909	2,029	(3,832)
Net (loss) income from discontinued operations	4	(4)	(4)	(11)	16	3	9	38	(15)	66	(193)
Net income	378	664	1,035	817	1,209	245	335	306	2,894	2,095	(4,025)
Net loss (income) and preferred dividends attributable to noncontrolling interests	107	(108)	(166)	(125)	(168)	35	(66)	(75)	(292)	(274)
Net income from discontinued operations attributable to noncontrolling interests					0	0	(1)	(3)	0	(4)	(63)
Net income (loss) attributable to common stockholders	$ 485	$ 556	$ 869	$ 692	$ 1,041	$ 280	$ 268	$ 228	$ 2,602	$ 1,817	$ (4,154)
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.33	$ 0.38	$ 0.60	$ 0.48	$ 0.71	$ 0.19	$ 0.18	$ 0.13	$ 1.80	$ 1.21	$ (2.96)
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share	0.00	0.00	0.00	(0.01)	0.01	0.00	0.00	0.03	(0.01)	0.04	(0.20)
Earnings Per Share, Basic	$ 0.33	$ 0.38	$ 0.60	$ 0.47	$ 0.72	$ 0.19	$ 0.18	$ 0.16	$ 1.79	$ 1.25	$ (3.16)
Weighted Average Number of Shares Outstanding, Basic	1,450,000,000	1,450,000,000	1,449,000,000	1,449,000,000	1,448,000,000	1,448,000,000	1,447,000,000	1,446,000,000	1,449,000,000	1,447,000,000	1,318,000,000
Income (Loss) from Continuing Operations, Per Diluted Share	$ 0.33	$ 0.38	$ 0.59	$ 0.48	$ 0.70	$ 0.19	$ 0.18	$ 0.13	$ 1.79	$ 1.21	$ (2.96)
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	0.00	0.00	0.00	(0.01)	0.01	0.00	0.00	0.03	(0.01)	0.04	(0.20)
Earnings Per Share, Diluted	$ 0.33	$ 0.38	$ 0.59	$ 0.47	$ 0.71	$ 0.19	$ 0.18	$ 0.16	$ 1.78	$ 1.25	$ (3.16)
Weighted Average Number of Shares Outstanding, Diluted	1,457,000,000.00	1,458,000,000.00	1,458,000,000.00	1,458,000,000.00	1,455,000,000	1,454,000,000	1,453,000,000	1,454,000,000	1,458,000,000.00	1,454,000,000	1,318,000,000