Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2012

Stock-Based Compensation

Assumptions used to determine the grant date fair value for options granted

	2012	2011	2010
Range of risk-free interest rate	0.62%-1.03%	0.90% - 2.24%	1.41% - 2.39%
Weighted average risk-free interest rate	0.92%	1.97%	2.35%
Expected life of option grants	4.40 years	4.50 years	4.60 years
Range of expected volatility of underlying stock price	36.53% - 37.86%	36.89% - 38.13%	37.11% - 37.48%
Weighted average expected volatility of underlying stock price	37.84%	36.98%	37.14%
Weighted average expected annual dividends	1.50%	0.03%	N/A

Summary of the company's option activity

	Options	Weighted Average Exercise Price		Weighted Average Contractual Term (Years)		Aggregate Intrinsic Value (in millions)
Outstanding as of January 1, 2012	6,376,244	$	37.36
Granted	1,237,172		62.22
Exercised	(1,614,657)		31.53
Forfeited	(162,839)		44.19
Expired	(5,975)		9.74
Outstanding as of December 31, 2012	5,829,945	$	44.09	6.42	$	193.45
Exercisable as of December 31, 2012	3,170,504	$	37.07	4.86	$	127.46
Vested or expected to vest as of December 31, 2012	5,829,945	$	44.09	6.42	$	193.45

Schedule of options outstanding

Options Outstanding					Options Exercisable
Outstanding Number of Options	Range of Exercise Price Per Share	Weighted Average Exercise Price Per Share		Weighted Average Remaining Life (Years)	Options Exercisable	Weighted Average Exercise Price Per Share
703,811	$5.51 - $28.39	$	26.32	5.47	458,581	$	25.22
733,695	31.06 - 31.54		31.49	3.52	691,370		31.50
972,017	32.21- 37.70		37.52	4.50	970,173		37.53
1,237,938	38.06 - 47.25		43.41	6.07	823,641		43.56
966,548	50.78- 58.60		51.25	8.23	198,019		51.14
1,215,936	62.00- 71.50		62.22	9.20	28,720		62.00
5,829,945	$5.51 - $71.50	$	44.09	6.42	3,170,504	$	37.07

Summary of the company's restricted stock unit activity

	Number of Units	Weighted Average Grant Date Fair Value
Outstanding as of January 1, 2012	2,197,460	$	42.39
Granted	836,835		62.34
Vested	(893,739)		39.75
Forfeited	(172,003)		48.20
Outstanding as of December 31, 2012	1,968,553	$	51.56
Expected to vest, net of estimated forfeitures, as of December 31, 2012	1,898,708	$	51.37

Schedule of employee stock purchase plan valuation assumptions

	2012	2011	2010
Range of risk-free interest rate	0.05% - 0.12%	0.11% - 0.20%	0.22% - 0.23%
Weighted average risk-free interest rate	0.08%	0.16%	0.22%
Expected life of shares	6 months	6 months	6 months
Range of expected volatility of underlying stock price	33.16% - 33.86%	33.96% - 34.55%	35.26% - 35.27%
Weighted average expected volatility of underlying stock price	33.54%	34.28%	35.26%
Expected annual dividends	1.50%	N/A	N/A