Share-Based Compensation (Summary Of Share Options Outstanding And Exercisable) (Details) (USD $) In Millions, except Share data				9 Months Ended
	Sep. 30, 2011		Dec. 31, 2010	Sep. 30, 2011 $30.06-$41.16 [Member]		Sep. 30, 2011 $42.90-$45.53 [Member]		Sep. 30, 2011 $48.02-$73.32 [Member]
Range of Exercise Prices, Minimum				$ 30.06		$ 42.90		$ 48.02
Range of Exercise Prices, Maximum				$ 41.16		$ 45.53		$ 73.32
Outstanding Options, Number	1,345,963	[1]	1,847,136	473,684	[1]	466,060	[1]	406,219	[1]
Outstanding Options, Weighted Average Price	$ 42.26	[1]	$ 42.39	$ 32.08	[1]	$ 44.32	[1]	$ 51.77	[1]
Exercisable Options, Number	861,844	[1]		179,979	[1]	428,797	[1]	253,068	[1]
Exercisable Options, Weighted Average Price	$ 45.32	[1]		$ 35.38	[1]	$ 44.36	[1]	$ 54.03	[1]
Aggregate intrinsic value of outstanding options	$ 18.3
Aggregate Intrinsic Value of Exercisable Options	$ 9.3
Closing share price per share for calculation of aggregate intrinsic values	$ 55.26

[1] The aggregate intrinsic values of outstanding options and exercisable options at September 30, 2011 were $18.3 million and $9.3 million, respectively. The aggregate intrinsic values were calculated as the excess, if any, between our closing share price of $55.26 per share on September 30, 2011 and the strike price of the underlying award.