Basic and Diluted Earnings Per Share (Details) (USD $) In Millions, except Per Share data	3 Months Ended				6 Months Ended
	Jun. 30, 2011		Jun. 30, 2010		Jun. 30, 2011		Jun. 30, 2010
Notes to Financial Statements [Abstract]
Net Income	$ 294		$ 204		$ 308		$ 441
Earnings Adjustment from Assumed Conversion of Dilutive Shares of Common Stock in Rabbi Trust	(4)	[1]	(9)	[1]	0	[1]	(7)	[1]
Net Income Used for Diluted Earnings Per Share Calculation	$ 290		$ 195		$ 308		$ 434
Weighted Average Number of Shares Outstanding, Basic (in shares)	176		175		176		175
Incremental Shares from Assumed Conversion of Dilutive Stock Options, Restricted Stock and Shares of Common Stock in Rabbi Trust (in shares)	3		3		2		3
Weighted Average Number of Shares Outstanding, Diluted (in shares)	179		178		178		178
Earnings Per Share, Basic (in dollars per share)	$ 1.66		$ 1.17		$ 1.75		$ 2.53
Earnings Per Share, Diluted (in dollars per share)	$ 1.61		$ 1.10		$ 1.73		$ 2.44
Number of antidilutive stock options, shares of restricted stock and shares of common stock in rabbi trust excluded from calculation above	2		2		3		2

[1] The diluted earnings per share calculation includes a decrease to net income related to a deferred compensation gain from shares of our common stock held in a rabbi trust. When dilutive, the deferred compensation gain or loss (net of tax) is excluded from net income while the shares of our common stock held in the rabbi trust are included in the outstanding diluted share count.