Earnings Per Share (Details) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share [Abstract]
Anti-dilutive shares not included in diluted common share outstanding (in shares)	0	0.3
Weighted-average basic common shares outstanding (in shares)	179.7	177.0
Potential number of shares issuable upon excerise of in-the-money stock options under the Long-term Stock Incentive Plan	0.3	0
Average diluted common shares outstanding (in shares)	180.0	177.0