Income Taxes - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015		Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2013
Income Tax [Line Items]
Repatriation of foreign cash			$ 93.0
Income taxes	$ 45.8	$ 46.2	103.9		$ 100.3
Cash and cash equivalents	203.2	$ 196.9	203.2		196.9	$ 423.0	$ 496.9
Deferred tax benefit			(9.4)	[1]	$ 0.0
Foreign Cash Repatriated
Income Tax [Line Items]
Income taxes			2.7
Deferred tax benefit			11.6
Outside U.S.
Income Tax [Line Items]
Cash and cash equivalents	$ 149.2		$ 149.2

[1] See Note 18 for a discussion of the tax impact of foreign cash repatriation.