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 [Member]	Retained Earnings [Member] Preferred Class A [Member]	Retained Earnings [Member] Preferred Class B [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Loss [Member]	Noncontrolling Interests [Member]
Balance at Dec. 31, 2014	$ 14,794			$ 55	$ 3	$ 1,304	$ 9,284	$ 9,379			$ (3,042)	$ (4,677)	$ 2,488
Net income (loss)	255							195					60
Other comprehensive loss (C)	(1,162)											(914)	(248)
Cash dividends declared:
Preferred share, value		$ (1)	$ (17)						$ (1)	$ (17)
Common share, value	(36)							(36)
Stock-based compensation	26						26
Common stock issued: compensation plans	15						(186)				201
Distributions	(29)												(29)
Other	(2)												(2)
Balance at Mar. 31, 2015	13,843			55	3	1,304	9,124	9,520			(2,841)	(5,591)	2,269
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 loss (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