Summary Of Significant Accounting Policies (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Dec. 31, 2011
Summary Of Significant Accounting Policies [Line Items]
Percentage inventory valued under LIFO	76.00%	78.00%
Higher inventory if FIFO applied entirely	$ 103.3	$ 96.1
Increase in cost of goods sold due to LIFO accounting method	7.2
Effect of LIFO inventory liquidation on income	2.4
LIFO expense related to inflation	9.6
Warehousing and administrative expenses charged to inventory	33.3	33.8
Outstanding checks	69.7	71.4
Buildings [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life, maximum years	40
Fixtures And Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life, minimum years	2
Estimated useful life, maximum years	10
Capitalized Software [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life, maximum years	10
Customer Rebates [Member]
Summary Of Significant Accounting Policies [Line Items]
Accrued liabilities	36.4	55.7
Supplier Allowances [Member]
Summary Of Significant Accounting Policies [Line Items]
Receivables related to supplier allowances	$ 60.2	$ 81.3