Revenue Recognition and Accounts Receivable (Narrative) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Revenue Recognition And Accounts Receivable [Line Items]
Sales allowances, current	$ 1,820.0	$ 1,980.0
Accrued sales allowances and other adjustments	626.1	818.0
Securitized accounts receivable	493.7	$ 1,040.0
Receivables Facility
Revenue Recognition And Accounts Receivable [Line Items]
Accounts receivable securitization facility maximum borrowing capacity	$ 400.0