Share-Based Compensation (Summary Of Stock Option Activity) (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Shares Under Option
Outstanding at December 31, 2011	3,995,000
Granted	1,221,000	200,000
Exercised	(197,000)
Cancelled / forfeited / expired	(245,000)
Outstanding at March 31, 2012	4,774,000		3,995,000
Exercisable at March 31, 2012	819,000
Weighted Average Exercise Price
Outstanding at December 31, 2011	$ 20.75
Granted	$ 13.22
Exercised	$ 7.09
Cancelled / forfeited / expired	$ 30.73
Outstanding at March 31, 2012	$ 18.87		$ 20.75
Exercisable at March 31, 2012	$ 7.09
Weighted Average Remaining Contractual Term (years)
Outstanding at December 31, 2011	6 years 10 months 24 days		5 years 10 months 24 days
Granted	9 years 10 months 24 days
Outstanding at March 31, 2012	6 years 10 months 24 days		5 years 10 months 24 days
Exercisable at March 31, 2012	6 years 10 months 24 days
Aggregate Intrinsic Value
Outstanding at December 31, 2011	$ 9.5
Outstanding at March 31, 2012	5.8		9.5
Exercisable at March 31, 2012	$ 4.3