Accounts Receivable, Net (Summary of Reserve for Discounts and Allowances) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Provision for discounts and doubtful accounts
As of January 1,	$ 169.6	$ 55.8	$ 48.5
Provision charged to operations	1,408.1	838.1	424.2
Payments/credits	(1,306.2)	(724.3)	(416.9)
As of December 31,	$ 271.5	$ 169.6	$ 55.8