Subsequent Events (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended		1 Months Ended	3 Months Ended
	Apr. 30, 2014 4.20% Notes	Apr. 03, 2014 4.20% Notes	Apr. 30, 2014 6.25% Notes	Mar. 31, 2014 6.25% Notes
Subsequent Event [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.20%		6.25%
Debt Instrument, Face Amount		$ 500.0
Debt Instrument, Unamortized Discount		0.9		0.1
Debt Related Commitment Fees and Debt Issuance Costs		4.4
Debt Instrument, Maturity Date	Apr. 15, 2024			Nov. 15, 2014
Proceeds from Issuance of Long-term Debt	494.7
Debt Instrument, Frequency of Periodic Payment	semi-annually
Debt Instrument, Date of First Required Payment	Oct. 15, 2014
Extinguishment of Debt, Amount			350.0
Senior Notes Redemption Date			May 05, 2014
Loss on Extinguishment of Debt			$ (10.0)