Consolidated Statements of Changes in Equity (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, 2009		$ 3,257	$ 3,168	$ (147)	$ 38	$ 6,316
Beginning Balance, shares at Dec. 31, 2009		165,400,000
Net Income	639		630			639
Net Income (Loss) Attributable to Noncontrolling Interest	9				9
Dividends declared on common stock			(367)			(367)
Stock Issued During Period, Shares, New Issues		777,000
Issuance of common stock, value		36				36
Benefit obligations, net of tax	15			15		15
Foreign currency translation, net of tax	1			1		1
Net change in unrealized losses on derivatives, net of tax				2		2
Net change in unrealized losses on investments, net of tax				(20)		(20)
Stock-based compensation, distributions to noncontrolling interests and other, shares		1,027,000
Stock-based compensation, distributions to noncontrolling interests and other		47				45
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders					(2)
Contribution of Common Stock to Pension Plan Shares		2,224,000
Contribution of Common Stock to Pension Plan		100				100
Ending Balance at Dec. 31, 2010		3,440	3,431	(149)	45	6,767
Ending Balance, shares at Dec. 31, 2010		169,428,000
Beginning Balance at Sep. 30, 2010
Net Income			711			720
Dividends declared on common stock			(392)			(392)
Issuance of common stock, value						36
Ending Balance at Dec. 31, 2010		3,440	3,431	(149)	45	6,767
Beginning Balance, shares at Dec. 31, 2010		169,428,000
Net Income	720
Net Income (Loss) Attributable to Noncontrolling Interest	9				9
Treasury Stock, Shares, Acquired		(1,184,000)
Treasury Stock, Value		(58)
Issuance of common stock, value	3,417					(58)
Benefit obligations, net of tax	(9)			(9)		(9)
Foreign currency translation, net of tax	0
Stock-based compensation, distributions to noncontrolling interests and other, shares		1,003,000
Stock-based compensation, distributions to noncontrolling interests and other		35				25
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders					(10)
Ending Balance at Dec. 31, 2011	7,053	3,417	3,750	(158)	44	7,053
Ending Balance, shares at Dec. 31, 2011	169,247,282	169,247,000
Net Income	618		610			618
Net Income (Loss) Attributable to Noncontrolling Interest	8
Dividends declared on common stock			(414)			(414)
Stock Issued During Period, Shares, New Issues		684,000
Issuance of common stock, value	3,587	39				39
Benefit obligations, net of tax	(2)			(2)		(2)
Foreign currency translation, net of tax	1			1
Net change in unrealized losses on derivatives, net of tax	0
Net change in unrealized losses on investments, net of tax				1		1
Stock-based compensation, distributions to noncontrolling interests and other, shares		1,086,000
Stock-based compensation, distributions to noncontrolling interests and other		51				35
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders					(14)
Contribution of Common Stock to Pension Plan Shares		1,335,000
Contribution of Common Stock to Pension Plan		80				80
Repurchase of common stock						1
Ending Balance at Dec. 31, 2012	$ 7,411	$ 3,587	$ 3,944	$ (158)	$ 38	$ 7,411
Ending Balance, shares at Dec. 31, 2012	172,351,680	172,352,000