Income Tax (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Operating Loss Carryforwards [Line Items]
Effective tax rate (as a percent)	20.00%	11.00%	19.00%	8.00%
Federal statutory income tax rate (percent)			35.00%
Net discrete tax benefit	$ 0.2	$ (12.2)
Out of period adjustment		8.7
Bilateral Advanced Pricing Agreement (BAPA) [Member]
Operating Loss Carryforwards [Line Items]
Net discrete tax benefit		$ (21.0)