Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2013

Share-based Compensation, Allocation and Classification in Financial Statements [Abstract]

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

Key assumptions used to apply this pricing model are as follows:

	2013	2012	2011
Range of risk-free interest rate	0.75% - 1.42%	0.62% - 1.03%	0.90% – 2.24%
Weighted average risk-free interest rate	0.91%	0.92%	1.97%
Expected life of option grants	4.41 years	4.40 years	4.50 years
Range of expected volatility of underlying stock price	24.43% - 36.09%	36.53% - 37.86%	36.89% – 38.13%
Weighted average expected volatility of underlying stock price	33.37%	37.84%	36.98%
Expected annual dividend yield	1.50%	1.50%	0.03%

Summary of the company's option activity

The following table summarizes the Company’s option activity for the periods presented:

	Options		Weighted Average Exercise Price		Weighted Average Contractual Term (Years)	Aggregate Intrinsic Value (in millions)
Outstanding as of January 1, 2013	5,829,945		$	44.09
Granted	1,449,261		76.89
Exercised	(1,081,437	)	37.52
Forfeited	(91,298	)	59.27
Expired	(300	)	9.94
Outstanding as of December 31, 2013	6,106,171		$	52.81	6.52	$	164.9
Exercisable as of December 31, 2013	3,196,741		$	40.54	4.81	$	125.6
Vested or expected to vest as of December 31, 2013	6,104,707		$	52.81	6.52	$	164.9

Schedule of options outstanding

The following table sets forth information regarding options outstanding at December 31, 2013:

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
808,812	$10.68 - $35.72	$27.94	3.97	808,812	$27.94
1,913,223	37.52 - 47.25	40.64	4.33	1,729,532	40.38
854,664	50.78 - 58.60	51.23	7.20	376,970	51.14
1,131,753	62.00 - 74.06	62.54	8.20	255,515	62.23
1,397,719	76.90 - 79.05	76.95	9.20	25,912	76.90
6,106,171	$10.68 - $79.05	$52.81	6.52	3,196,741	$40.54

Summary of the company's restricted stock unit activity

The following table summarizes the Company’s restricted stock unit activity during the year ended December 31, 2013:

	Number of Units		Weighted Average Grant Date Fair Value
Outstanding as of January 1, 2013	1,968,553		$	51.56
Granted	828,218		76.88
Vested	(817,966	)	45.92
Forfeited	(138,668	)	61.00
Outstanding as of December 31, 2013	1,840,137		$	64.75
Expected to vest, net of estimated forfeitures, as of December 31, 2013	1,769,009		$	64.54

Schedule of employee stock purchase plan valuation assumptions

Key assumptions used to apply the Black-Scholes pricing model for shares purchased through the ESPP for the years ended December 31, are as follows:

	2013	2012	2011
Range of risk-free interest rate	0.07% – 0.13%	0.05% – 0.12%	0.11% – 0.20%
Weighted average risk-free interest rate	0.10%	0.08%	0.16%
Expected life of shares	6 months	6 months	6 months
Range of expected volatility of underlying stock price over the option period	12.21% – 13.57%	33.16% – 33.86%	33.96% – 34.55%
Weighted average expected volatility of underlying stock price	12.88%	33.54%	34.28%
Expected annual dividend yield	1.50%	1.50%	N/A