Earnings Per Share (Details) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]
Weighted-average basic common shares outstanding (in shares)	180.1	179.3	180.0	179.2
Potential number of shares issuable upon excerise of in-the-money stock options under the Long-term Stock Incentive Plan	0.5	0.2	0.4	0.2
Average diluted common shares outstanding (in shares)	180.6	179.5	180.4	179.4