Share-Based Compensation (Summary Of Stock Appreciation Rights) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options, Outstanding at December 31, 2010	2,585,385
Number of Rights, Granted	629,789
Number of Rights, Exercised	(244,944)
Number of Rights, Expired or cancelled	(319,367)
Number of Options, Outstanding at December 31, 2011	2,650,863
Number of Rights, Exercisable at December 31, 2011	1,792,691
Weighted-Average Exercise Price, Outstanding at December 31, 2010	$ 36.41
Weighted-Average Exercise Price, Granted	$ 32.37
Weighted-Average Exercise Price, Exercised	$ 22.59
Weighted-Average Exercise Price, Expired or cancelled	$ 45.85
Weighted- Average Exercise Price, Outstanding at December 31, 2011	$ 35.59
Weighted-Average Exercise Price, Exercisable at December 31, 2011	$ 38.76
Stock Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options, Outstanding at December 31, 2010	627,746
Number of Rights, Exercised	(63,123)
Number of Rights, Expired or cancelled	(41,517)
Number of Options, Outstanding at December 31, 2011	523,106
Number of Rights, Exercisable at December 31, 2011	173,465
Weighted-Average Exercise Price, Outstanding at December 31, 2010	$ 28.92
Weighted-Average Exercise Price, Exercised	$ 28.92
Weighted-Average Exercise Price, Expired or cancelled	$ 28.92
Weighted- Average Exercise Price, Outstanding at December 31, 2011	$ 28.92
Weighted-Average Exercise Price, Exercisable at December 31, 2011	$ 28.92