Stock-Based Compensation (Narrative) (Details) (USD $) In Millions, except Share data	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Apr. 30, 2011 2010 Plan [Member] New Number Of Shares Authorized [Member]	Apr. 30, 2011 2010 Plan [Member] Old Number Of Shares Authorized [Member]	Jul. 01, 2011 2009 Plan [Member] New Number Of Shares Authorized [Member]	Jul. 01, 2011 2009 Plan [Member] Old Number Of Shares Authorized [Member]
Number of shares of common stock authorized for issuance					2,450,000	1,250,000	530,000	350,000
Options exercisable, number of shares	2,500,000		2,500,000
Options exercisable, weighted-average exercise price per share	$ 194.58		$ 194.58
Employee stock purchase plan, shares issued	0	0	92,072	82,948
Employee stock purchase plan, value of shares issued			$ 10.4	$ 7.7