Share-Based Compensation (Stock Option Awards) (Details) (USD $)			12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 $33.61-40.53 [Member] years	Dec. 31, 2011 $41.34-51.43 [Member] years	Dec. 31, 2011 $51.51-58.83 [Member] years
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit			$ 33.61	$ 41.34	$ 51.51
Options Outstanding, Number of Options	544,225	615,676	170,525	177,700	196,000
Options Outstanding, Weighted-Avg. Remaining Contractual Life (Years)	5.2		6.9	4.7	4.3
Options Outstanding, Weighted-Avg. Exercise Price	$ 46.09	$ 45.06	$ 34.32	$ 47.74	$ 54.82
Options Exercisable, Number of Options	408,824		78,025	147,699	183,100
Options Exercisable, Weighted-Avg. Exercise Price	$ 48.45		$ 34.82	$ 47.55	$ 54.97