Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2011

Earnings Per Share [Abstract]

Schedule Of Weighted Average Number Of Shares Basic And Diluted

A reconciliation of the components of basic and diluted shares used in the EPS calculation follows:

	Year Ended December 31,
	2011	2010	2009
	(in millions)
Weighted-average basic common shares outstanding	177.4	175.4	174.1
Potential number of shares issuable under the LTSIP	1.4	2.6	2.2
Average diluted common shares outstanding	178.8	178.0	176.3