Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Statement Of Financial Position [Abstract]
Trade receivables, net of allowance for doubtful accounts	$ 27.5	$ 28.8
Preferred stock, par value per share	$ 0.10	$ 0.10
Preferred stock, shares authorized	50,000,000us-gaap_PreferredStockSharesAuthorized	50,000,000us-gaap_PreferredStockSharesAuthorized
Preferred stock, shares issued	0us-gaap_PreferredStockSharesIssued	0us-gaap_PreferredStockSharesIssued
Common stock, par value per share	$ 0.10	$ 0.10
Common stock, shares authorized	400,000,000us-gaap_CommonStockSharesAuthorized	400,000,000us-gaap_CommonStockSharesAuthorized
Common stock, shares issued	225,609,374us-gaap_CommonStockSharesIssued	224,683,653us-gaap_CommonStockSharesIssued
Common stock, shares outstanding	210,622,311us-gaap_CommonStockSharesOutstanding	210,531,894us-gaap_CommonStockSharesOutstanding
Common stock in treasury, shares	14,987,063us-gaap_TreasuryStockShares	14,151,759us-gaap_TreasuryStockShares

A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible.

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