Income Taxes - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Other Tax Expense (Benefit) [Line Items]
Effective income tax rate	21.50%	19.00%	19.70%	20.00%
Federal statutory income tax rate			21.00%	35.00%
Release of valuation allowances			$ 8.5	$ 9.8
Discrete tax benefit related to TCJA			6.5
Excess tax benefits			7.2	4.7
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	$ 3.1		6.1
Gain on sale of business
Other Tax Expense (Benefit) [Line Items]
Other tax expense (benefit)			42.0
Tax accounting method change
Other Tax Expense (Benefit) [Line Items]
Other tax expense (benefit)			$ (8.0)
Foreign rate changes
Other Tax Expense (Benefit) [Line Items]
Other tax expense (benefit)				13.1
Out-of-period adjustments
Other Tax Expense (Benefit) [Line Items]
Other tax expense (benefit)				$ 5.1