Consolidated Statements of Changes in Equity (Unaudited) (USD $) In Millions, except Share data	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Loss	Non-controlling Interest	Stockholders' Equity, Total [Member]
Beginning Balance at Dec. 31, 2012	$ 7,411	$ 3,587	$ 3,944	$ (158)	$ 38	$ 7,411
Beginning Balance, shares at Dec. 31, 2012	172,351,680	172,352,000
Net Income	235		234			235
Net Income (Loss) Attributable to Noncontrolling Interest	1				1
Dividends declared on common stock			(107)			(107)
Stock Issued During Period, Shares, New Issues		158,000
Issuance of common stock, value	3,683	10				10
Contribution of Common Stock to Pension Plan Shares	750,075	750,000
Contribution of Common Stock to Pension Plan	50	50				50
Foreign currency translation, net of tax	(1)			(1)
Benefit obligations, net of tax	3			3		3
Stock-based compensation, distributions to noncontrolling interests and other, shares		691,000
Stock-based compensation, distributions to noncontrolling interests and other		36				31
Stockholders' Equity, Other			(2)
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders					(3)
Ending Balance at Mar. 31, 2013	$ 7,632	$ 3,683	$ 4,069	$ (156)	$ 36	$ 7,632
Ending Balance, shares at Mar. 31, 2013	173,950,853	173,951,000