Statement of Changes in Consolidated Equity (unaudited) - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Non-controlling Interest [Member]
Beginning Balance at Dec. 31, 2017	$ 6,968	$ 2	$ 9,590	$ 318	$ (5,182)	$ 2,240
Net (loss) income	340			195		145
Other comprehensive income (loss) (F)	619				652	(33)
Stock-based compensation	10		10
Common stock issued: compensation plans	15		15
Contributions	53					53
Distributions	(267)					(267)
Other	15		18			(3)
Ending Balance at Mar. 31, 2018	7,753	2	9,633	513	(4,530)	2,135
Beginning Balance at Dec. 31, 2018	7,588	2	9,611	570	(4,565)	1,970
Net (loss) income	(58)			(199)		141
Other comprehensive income (loss) (F)	(260)				(269)	9
Stock-based compensation	10		10
Common stock issued: compensation plans	1		1
Contributions	20					20
Distributions	(214)					(214)
Other	(4)		(4)
Ending Balance at Mar. 31, 2019	$ 7,083	$ 2	$ 9,618	$ 371	$ (4,834)	$ 1,926