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 Dec. 31, 2011	$ 17,195	$ 55	$ 1,178	$ 7,561	$ 11,629	$ (3,952)	$ (2,627)	$ 3,351
Net income	99				94			5
Other comprehensive income	286						221	65
Cash dividends declared:
Preferred @ $0.9375 per share	(1)				(1)
Common @ $0.03 per share	(32)				(32)
Stock-based compensation	19			19
Common stock issued: compensation plans	(3)			(57)		54
Distributions	(26)							(26)
Contributions	90							90
Other	(1)							(1)
Balance at Mar. 31, 2012	17,626	55	1,178	7,523	11,690	(3,898)	(2,406)	3,484
Balance at Dec. 31, 2012	16,523	55	1,178	7,560	11,689	(3,881)	(3,402)	3,324
Net income	170				149			21
Other comprehensive income	112						93	19
Cash dividends declared:
Preferred @ $0.9375 per share	(1)				(1)
Common @ $0.03 per share	(32)				(32)
Stock-based compensation	23			23
Common stock issued: compensation plans	(10)			(75)		65
Distributions	(25)							(25)
Contributions	15							15
Other	(1)							(1)
Balance at Mar. 31, 2013	$ 16,774	$ 55	$ 1,178	$ 7,508	$ 11,805	$ (3,816)	$ (3,309)	$ 3,353