SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance for Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 11.1	$ 10.5	$ 9.3
Charged to Cost and Expenses	3.0	2.2	2.8
Other Deductions	(0.6)	(1.6)	(1.6)
Balance at End of Year	13.5	11.1	10.5
Allowance For Volume And Early Payment Discounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	23.0	22.6	23.4
Charged to Cost and Expenses	100.4	80.1	51.6
Other Deductions	(92.7)	(79.7)	(52.4)
Balance at End of Year	30.7	23.0	22.6
Allowance for Sales Returns [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	47.2	39.3	45.4
Charged to Cost and Expenses	68.3	64.5	48.5
Other Deductions	(55.7)	(56.6)	(54.6)
Balance at End of Year	$ 59.8	$ 47.2	$ 39.3