Stockholders' Equity (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Components of Stockholders' Equity [Line Items]
Stock repurchase plan, authorized amount			$ 300,000,000
Repurchases of common stock, shares	182,000		899,847
Average price per share of common stock repurchased	$ 218		$ 222
Aggregate amount of common stock repurchased	39,600,000		199,700,000
Stock repurchase program, remaining authorized repurchase amount			41,000,000
Unsettled share repurchases	0		0
Acquisition costs related to share repurchase	7,800,000		40,900,000
Total intrinsic value of options exercised	32,200,000	44,800,000	125,600,000	100,700,000
Cash received from option exercised	4,400,000	10,900,000	18,600,000	34,000,000
Weighted-average fair value of employee stock options granted per share	$ 137.90	$ 56.55	$ 127.41	$ 40.96
Cash received from the issuance of common stock	$ 4,409,000	$ 10,927,000	$ 18,589,000	$ 33,954,000
Executives [Member]
Components of Stockholders' Equity [Line Items]
Suboptimal exercise factor, minimum			$ 3.39	$ 2.15
Suboptimal exercise factor, maximum			$ 3.63	$ 2.40
Calculated expected life of the option grants (in years)			8	5
Non-Executives [Member]
Components of Stockholders' Equity [Line Items]
Suboptimal exercise factor, minimum			$ 2.17	$ 1.78
Suboptimal exercise factor, maximum			$ 2.26	$ 2.00
Calculated expected life of the option grants (in years)			5	4