Fair Value Measurements Fair Value Measurements, Textual (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Debt Instrument, Fair Value Disclosure [Abstract]
Derivative Asset	$ 0.3	$ 85.7
Minimum
Schedule of Available-for-sale Securities [Line Items]
Short-term investment maturity period	8 months
Maximum
Schedule of Available-for-sale Securities [Line Items]
Short-term investment maturity period	10 months
Derivative
Debt Instrument, Fair Value Disclosure [Abstract]
Fair Value, Net Asset (Liability)	$ (17.3)	$ (11.1)