Share-Based Compensation (Schedule Of Stock Option Activity) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011 years
Share-Based Compensation [Abstract]
Shares Outstanding at January 1, 2011	5,404,223
Granted, Shares	770,350
Exercised, Shares	(1,333,185)
Forfeited/Expired, Shares	(527,344)
Shares Outstanding at December 31, 2011	4,314,044
Shares Vested and expected to vest at December 31, 2011	3,659,049
Shares Exercisable at December 31, 2011	2,805,172
Stock Options Outstanding, Weighted Average Price, Beginning	$ 26.85
Granted, Weighted Average Price	$ 40.98
Exercised, Weighted Average Price	$ 24.10
Forfeited/Expired, Weighted Average Price	$ 31.79
Stock Options Outstanding, Weighted Average Price, Ending	$ 29.61
Vested and expected to vest at December 31, 2011, Weighted Average Price	$ 28.51
Exercisable at December 31, 2011, Weighted Average Price	$ 27.76
Weighted-Average Remaining Contractual Term, Beginning period	6.29
Exercisable, Weighted-Average Remaining Contractual Term	5.84
Vested and expected to vest at December 31, 2011, Weighted-Average Remaining Contractual Term	6.55
Weighted-Average Remaining Contractual Term, Ending period	7.01
Stock options outstanding, Beginning aggregate intrinsic value	$ 66,329,686
Stock options outstanding, Ending aggregate intrinsic value	34,899,200
Stock options, exercisable aggregate intrinsic value	26,371,747
Stock options, vested and expected to vest aggregate intrinsic value	$ 32,886,227