Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2012

Earnings Per Share [Abstract]

Calculation of Basic and Diluted Earnings (Loss) Per Share

The following table summarizes the calculation of basic and diluted earnings per share: 

	Year Ended December 31,
	2012		2011		2010
(millions, except per share amounts)
Income from Continuing Operations Used for Diluted Earnings Per Share Calculation	$	965	$	412	$	631
Weighted Average Number of Shares Outstanding, Basic	178		176		175
Incremental Shares From Assumed Conversion of Dilutive Stock Options and Restricted Stock	2		3		2
Weighted Average Number of Shares Outstanding, Diluted	180		179		177
Earnings from Continuing Operations Per Share, Basic	$	5.43	$	2.34	$	3.61
Earnings from Continuing Operations Per Share, Diluted	5.37		2.31		3.56
Additional Information
Number of antidilutive stock options, shares of restricted stock and shares of common stock in rabbi trust excluded from calculation above	3		3		2
Weighted average option exercise price per share	$	97.46	$	85.40	$	74.01