Debt - Summary of Debt (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 13, 2017	Dec. 31, 2016	Sep. 05, 2014	Oct. 22, 2013	Jun. 26, 2012	Mar. 25, 2008
Debt Instrument [Line Items]
Long-term debt	$ 2,645.7		$ 2,658.2
Less current portion	150.0		25.8
Less unamortized debt issuance costs	15.3		12.5
Long-term debt	$ 2,480.4		$ 2,620.0
Weighted-average interest rate	3.80%		3.54%
Revolving Credit Facility, due August 2021 | Line of Credit
Debt Instrument [Line Items]
Long-term debt	$ 0.0		$ 0.0
Stated interest rate	0.00%		0.00%
Five-Year Term Loan, due August 2021 | Unsecured Debt
Debt Instrument [Line Items]
Long-term debt	$ 0.0		$ 380.2
Stated interest rate	0.00%		2.02%
Seven-Year Term Loan, due October 2020 | Unsecured Debt
Debt Instrument [Line Items]
Long-term debt	$ 0.0		$ 630.5
Stated interest rate	0.00%		2.40%
6.50% Senior Notes due March 2018 | Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 150.0		$ 150.0
Stated interest rate	6.50%		6.50%				6.50%
2.45% Senior Notes, due December 2020 | Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 499.5		$ 0.0
Stated interest rate	2.45%	2.45%	0.00%
3.90% Senior Notes, due June 2022 | Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 399.8		$ 399.8
Stated interest rate	3.90%		3.90%			3.90%
4.50% Senior Notes, due November 2023 | Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 698.8		$ 698.6
Stated interest rate	4.50%		4.50%		4.50%
3.65% Senior Notes, due September 2024 | Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 399.2		$ 399.1
Stated interest rate	3.65%		3.65%	3.65%
3.40% Senior Notes, due December 2027 | Senior Notes
Debt Instrument [Line Items]
Long-term debt	$ 498.4		$ 0.0
Stated interest rate	3.40%	3.40%	0.00%
Current Portion of Long-term Debt
Debt Instrument [Line Items]
Weighted-average interest rate	6.50%		2.11%
Long-term Debt, Excluding Current Portion
Debt Instrument [Line Items]
Weighted-average interest rate	3.64%		3.57%