Statement of Changes in Consolidated Equity (USD $) In Millions, unless otherwise specified	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Loss [Member]	Noncontrolling Interests [Member]
Balance at Mar. 31, 2012	$ 17,626	$ 55	$ 1,178	$ 7,523	$ 11,690	$ (3,898)	$ (2,406)	$ 3,484
Net income (loss)	(19)				(2)			(17)
Other comprehensive income (loss)	(659)						(472)	(187)
Cash dividends declared:
Preferred @ $0.9375 for three month ended June 30, 2013 & 2012 and $1.875 for six month ended June 30, 2013 & 2012 per share
Common @ $0.03 for three month ended June 30, 2013 & 2012 and $0.06 for six month ended June 30, 2013 & 2012 per share	(33)				(33)
Stock-based compensation	20			20
Common stock issued: compensation plans	3			(5)		8
Distributions	(45)							(45)
Contributions	20							20
Other	1							1
Balance at Jun. 30, 2012	16,914	55	1,178	7,538	11,655	(3,890)	(2,878)	3,256
Balance at Dec. 31, 2011	17,195	55	1,178	7,561	11,629	(3,952)	(2,627)	3,351
Net income (loss)	80				92			(12)
Other comprehensive income (loss)	(373)						(251)	(122)
Cash dividends declared:
Preferred @ $0.9375 for three month ended June 30, 2013 & 2012 and $1.875 for six month ended June 30, 2013 & 2012 per share	(1)				(1)
Common @ $0.03 for three month ended June 30, 2013 & 2012 and $0.06 for six month ended June 30, 2013 & 2012 per share	(65)				(65)
Stock-based compensation	39			39
Common stock issued: compensation plans				(62)		62
Distributions	(71)							(71)
Contributions	110							110
Balance at Jun. 30, 2012	16,914	55	1,178	7,538	11,655	(3,890)	(2,878)	3,256
Balance at Dec. 31, 2012	16,523	55	1,178	7,560	11,689	(3,881)	(3,402)	3,324
Net income (loss)	22				30			(8)
Other comprehensive income (loss)	(611)						(381)	(230)
Cash dividends declared:
Preferred @ $0.9375 for three month ended June 30, 2013 & 2012 and $1.875 for six month ended June 30, 2013 & 2012 per share	(1)				(1)
Common @ $0.03 for three month ended June 30, 2013 & 2012 and $0.06 for six month ended June 30, 2013 & 2012 per share	(65)				(65)
Stock-based compensation	46			46
Common stock issued: compensation plans	(13)			(82)		69
Distributions	(53)							(53)
Contributions	12							12
Other	(2)							(2)
Balance at Jun. 30, 2013	15,858	55	1,178	7,524	11,653	(3,812)	(3,783)	3,043
Balance at Mar. 31, 2013	16,774	55	1,178	7,508	11,805	(3,816)	(3,309)	3,353
Net income (loss)	(148)				(119)			(29)
Other comprehensive income (loss)	(723)						(474)	(249)
Cash dividends declared:
Preferred @ $0.9375 for three month ended June 30, 2013 & 2012 and $1.875 for six month ended June 30, 2013 & 2012 per share
Common @ $0.03 for three month ended June 30, 2013 & 2012 and $0.06 for six month ended June 30, 2013 & 2012 per share	(33)				(33)
Stock-based compensation	23			23
Common stock issued: compensation plans	(3)			(7)		4
Distributions	(28)							(28)
Contributions	(3)							(3)
Other	(1)							(1)
Balance at Jun. 30, 2013	$ 15,858	$ 55	$ 1,178	$ 7,524	$ 11,653	$ (3,812)	$ (3,783)	$ 3,043