Share-Based Compensation (Share-Based Compensation Options Outstanding Rollforward) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-Based Compensation [Abstract]
Options outstanding January 1, Number of Options	2,591,066	2,950,892	3,695,668
Granted, Number of Options	35,000	135,000	180,000
Exercised, Number of Options	(341,156)	(448,826)	(782,151)
Cancelled, Number of Options	(31,400)	(46,000)	(142,625)
Options outstanding December 31, Number of Options	2,253,510	2,591,066	2,950,892
Options exercisable at December 31, Number of Options	1,401,883	1,200,356	1,063,283
Options outstanding January 1, Weighted Average Exercise Price Per Share	$ 74.30	$ 69.43	$ 64.96
Granted, Weighted Average Exercise Price Per Share	$ 144.97	$ 120.77	$ 87.59
Exercised. Weighted Average Exercise Price Per Share	$ 68.26	$ 58.86	$ 52.81
Cancelled, Weighted Average Exercise Price Per Share	$ 55.54	$ 48.95	$ 67.65
Options outstanding December 31, Weighted Average Exercise Price Per Share	$ 76.14	$ 74.30	$ 69.43
Options exercisable at December 31, Weighted Average Exercise Price Per Share	$ 76.23	$ 76.94	$ 74.27