Income Taxes - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective income tax rate	14.70%	22.40%
Federal statutory income tax rate	21.00%	35.00%
Provisional tax expense related to transition tax on foreign earnings			$ 429.2
Provisional tax benefit related to remeasurement of deferred tax balances			$ 62.3
Discrete tax benefit related to one-time transition tax	$ 2.8
Discrete tax benefit related to other provisions of TCJA	3.7
Income tax expense on global intangible low-taxed income	$ 3.0