Statement of Changes in Consolidated Equity (unaudited) - USD ($) $ in Millions	Total	Preferred Class A [Member]	Preferred Class B [Member]	Preferred Stock [Member]	Mandatory Convertible Preferred Stock [Member]	Common Stock [Member]	Additional Capital [Member]	Retained Earnings (Accumulated Deficit) [Member]	Retained Earnings (Accumulated Deficit) [Member] Preferred Class A [Member]	Retained Earnings (Accumulated Deficit) [Member] Preferred Class B [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Loss [Member]	Noncontrolling Interests [Member]
Balance at Dec. 31, 2015	$ 14,131			$ 55	$ 3	$ 1,391	$ 10,019	$ 8,834			$ (2,825)	$ (5,431)	$ 2,085
Net income (loss)	11							16					(5)
Other comprehensive income (C)	362											256	106
Cash dividends declared:
Preferred share, value		$ (1)	$ (17)						$ (1)	$ (17)
Common share, value	(79)							(79)
Stock-based compensation	26						26
Common stock issued: compensation plans	(21)						(189)				168
Distributions	(50)												(50)
Other	(1)												(1)
Balance at Mar. 31, 2016	14,361			55	3	1,391	9,856	8,753			$ (2,657)	(5,175)	2,135
Balance at Dec. 31, 2016	5,141			55	3	438	8,214	(1,027)				(2,568)	26
Net income (loss)	322							322
Other comprehensive income (C)	70											70
Cash dividends declared:
Preferred share, value		$ (1)	$ (16)						$ (1)	$ (16)
Common share, value	(54)							(54)
Stock-based compensation	28						28
Common stock issued: compensation plans	10					3	7
Distributions	(14)												(14)
Other	9							8					1
Balance at Mar. 31, 2017	$ 5,495			$ 55	$ 3	$ 441	$ 8,249	$ (768)				$ (2,498)	$ 13