Statement of Changes in Consolidated Equity (USD $) In Millions, unless otherwise specified	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, 2013	$ 13,522			$ 55		$ 1,178	$ 7,509	$ 9,272			$ (3,762)	$ (3,659)	$ 2,929
Net income (loss)	(197)							(178)					(19)
Other comprehensive income	447											358	89
Cash dividends declared:
Preferred share, value	(1)							(1)
Common share, value	(32)							(32)
Stock-based compensation	25						25
Common stock issued: compensation plans	51						(316)				367
Issuance of common stock	575					89	486
Distributions	(35)												(35)
Contributions	20												20
Other	(1)												(1)
Balance at Mar. 31, 2014	14,374			55		1,267	7,704	9,061			(3,395)	(3,301)	2,983
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 income	(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