Consolidated Statements Of Equity - USD ($) $ in Millions	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Stock [Member]	Noncontrolling Interest [Member]	Total
Balance, beginning at Dec. 31, 2012		$ 257	$ 4,640	$ 63	$ (484)	$ (369)	$ 12	$ 4,119
Balance (in shares) at Dec. 31, 2012		1,027,986,000				29,576,000
Stock plans			(19)			$ 31		12
Stock plans (in shares)						1,052,000
Dividends on common stock			(300)	(100)				(400)
Net income (loss)				113			2	115
Pension settlement costs, net of tax					27			27
Other comprehensive income (loss), net of tax					196			196
Distributions							(6)	(6)
Sale of Mohave partnership interest							$ (8)	(8)
Balance, ending at Dec. 31, 2013		$ 257	4,321	76	(261)	$ (338)		4,055
Balance (in shares) at Dec. 31, 2013		1,027,986,000				28,524,000
Stock plans			(30)			$ 44		14
Stock plans (in shares)						3,007,000
Dividends on common stock			(301)	(100)				(401)
Net income (loss)				133				133
Other comprehensive income (loss), net of tax					(143)			(143)
Balance, ending at Dec. 31, 2014		$ 257	3,990	109	(404)	$ (294)		$ 3,658
Balance (in shares) at Dec. 31, 2014		1,027,986,000				25,517,000		1,002,469,000
Issuance of stock (in shares)	19,250,000	165,000,000
Issuance of common stock		$ 41	758					$ 799
Issuance of preferred stock			1,866					1,866
Stock plans			(4)			$ 16		12
Stock plans (in shares)						731,000
Dividends on common stock			(456)					(456)
Dividends on preferred stock			(120)					(120)
Net income (loss)				(196)				(196)
Other comprehensive income (loss), net of tax					51			$ 51
Preferred Stock Balance (in shares) at Dec. 31, 2015	19,250,000							19,250,000
Balance, ending at Dec. 31, 2015		$ 298	$ 6,034	$ (87)	$ (353)	$ (278)		$ 5,614
Balance (in shares) at Dec. 31, 2015		1,192,986,000				24,786,000		1,168,200,000