Impact of Recently Issued Accounting Guidance (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Impact of Recently Issued Accounting Standards—Adopted
Warehouse, delivery, selling, general and administrative	$ 470.0	$ 453.0	$ 1,422.1	$ 1,357.7
Other (income) expense, net	$ (2.6)	2.1	$ 2.1	3.4
Impact of Recently Issued Accounting Standards—Adopted | Improvements to Net Periodic Pension Costs and Net Periodic Postretirement Benefits Cost
Impact of Recently Issued Accounting Standards—Adopted
Warehouse, delivery, selling, general and administrative		(1.3)		(3.9)
Other (income) expense, net		$ 1.3		$ 3.9