Debt (Schedule Of Long-Term Debt) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Debt Instrument [Line Items]
Long-term debt non current	$ 908.7	$ 896.9
4.40% Notes Due 2021 [Member]
Debt Instrument [Line Items]
Long-term debt non current	496.8	496.4
Debt instrument interest rate	4.40%
Debt instrument maturity date	2021
2.875% Notes Due 2016 [Member]
Debt Instrument [Line Items]
Long-term debt non current	262.1	250.7
Debt instrument interest rate	2.875%
Debt instrument maturity date	2016
6.70% Notes Due 2026 [Member]
Debt Instrument [Line Items]
Long-term debt non current	$ 149.8	$ 149.8
Debt instrument interest rate	6.70%
Debt instrument maturity date	2026