Debt (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Feb. 05, 2014 Amendment Of Revolving Credit Facility [Member]	Dec. 31, 2013 2013 Senior Notes [Member]	Dec. 31, 2012 2013 Senior Notes [Member]	May 31, 2008 2013 Senior Notes [Member]	Dec. 31, 2013 2018 Senior Notes [Member]	Dec. 31, 2012 2018 Senior Notes [Member]	May 31, 2008 2018 Senior Notes [Member]	Dec. 31, 2013 2020 Senior Notes [Member]	Mar. 31, 2013 2020 Senior Notes [Member]	Dec. 31, 2012 2020 Senior Notes [Member]	Aug. 17, 2009 2009 Credit Facility [Member]	Jan. 18, 2012 2012 Credit Facility Amendment [Member]
Debt Instrument [Line Items]
Principal amount							$ 350.0			$ 300.0		$ 400.0
Senior note, coupon rate							5.90%			6.65%		5.125%
Pricing of senior note										99.73%		99.998%
Effective yield										6.687%		5.125%
Outstanding balance	699.6	649.6			0	350.0		299.6	299.6		400.0		0
Notes Payable, Current	0	350.0
Unamortized discount	0.4	0.4			0	0		0.4	0.4		0		0
Senior notes repurchase price, percentage of aggregate principal amount plus accrued and unpaid interest	101.00%
Loss on extinguishment of debt	3.3	0	0
Premium paid upon repayment of debt	3.2
Write-off of debt issuance costs	0.1
Maximum size of credit facility				650.0											500.0
Length of credit facility (years)														3 years	5 years
Numerator of minimum interest coverage ratio	3
Denominator of minimum interest coverage ratio	1
Numerator of maximum leverage ratio	3
Denominator Of Maximum Leverage Ratio	1
Current Multicurrency Revolving Credit Facilty	350.0			500.0										300.0	350.0
Interest paid, net	39.1	42.3	42.6
Interest costs, capitalized	$ 0	$ 0.3	$ 0.3