Cash Discounts And Doubtful Accounts (Schedule of Cash Discounts and Doubtful Accounts) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance	$ 6.2	$ 5.9	$ 6.0
Provision (Charged to Expense)	37.7	42.8	36.1
Deductions	(37.0)	(42.5)	(36.2)
Ending Balance	6.9	6.2	5.9
Allowance for cash discounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance	2.2	2.2	2.0
Provision (Charged to Expense)	35.1	35.8	33.2
Deductions	(34.4)	(35.8)	(33.0)
Ending Balance	2.9	2.2	2.2
Allowance for doubtful accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance	4.0	3.7	4.0
Provision (Charged to Expense)	2.6	7.0	2.9
Deductions	(2.6)	(6.7)	(3.2)
Ending Balance	$ 4.0	$ 4.0	$ 3.7