Statement of Changes in Consolidated Equity (unaudited) - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Capital [Member]	Retained Earnings (Deficit) [Member]	Accumulated Other Comprehensive Loss [Member]	Non-controlling Interest [Member]
Balance at Dec. 31, 2018	$ 7,588	$ 2	$ 9,611	$ 570	$ (4,565)	$ 1,970
Net (loss) income	(351)			(601)		250
Other comprehensive (loss) income (G)	(130)				(140)	10
Stock-based compensation	21		21
Common stock issued: compensation plans	1		1
Contributions	21					21
Distributions	(286)					(286)
Other	(5)		(4)			(1)
Balance at Jun. 30, 2019	6,859	2	9,629	(31)	(4,705)	1,964
Balance at Mar. 31, 2019	7,083	2	9,618	371	(4,834)	1,926
Net (loss) income	(293)			(402)		109
Other comprehensive (loss) income (G)	130				129	1
Stock-based compensation	11		11
Contributions	1					1
Distributions	(72)					(72)
Other	(1)					(1)
Balance at Jun. 30, 2019	6,859	2	9,629	(31)	(4,705)	1,964
Balance at Dec. 31, 2019	5,886	2	9,639	(555)	(4,974)	1,774
Net (loss) income	(11)			(117)		106
Other comprehensive (loss) income (G)	(476)				(306)	(170)
Stock-based compensation	17		17
Contributions	16					16
Distributions	(106)					(106)
Other	(2)		(1)			(1)
Balance at Jun. 30, 2020	5,324	2	9,655	(672)	(5,280)	1,619
Balance at Mar. 31, 2020	5,811	2	9,647	(476)	(4,898)	1,536
Net (loss) income	(150)			(197)		47
Other comprehensive (loss) income (G)	(287)				(382)	95
Stock-based compensation	9		9
Contributions	16					16
Distributions	(75)					(75)
Other			(1)	1
Balance at Jun. 30, 2020	$ 5,324	$ 2	$ 9,655	$ (672)	$ (5,280)	$ 1,619