STOCK-BASED COMPENSATION

9 Months Ended

Sep. 30, 2015

NOTE 2. STOCK-BASED COMPENSATION

Presented below is a summary of the stock-based compensation cost and associated tax benefit included in the accompanying consolidated statements of operations:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2015		2014		2015		2014
Stock-based compensation cost	$	22.1	$	19.3	$	66.5	$	59.9
Tax benefit	$	7.2	$	6.2	$	21.8	$	19.0

During the first nine months of 2015, the Company granted 0.3 million employee stock options, which had a weighted average grant date fair value of $36.08 per share based on the Black-Scholes option-pricing model. The Company also granted 0.9 million shares of restricted stock in the first nine months of 2015, which had a weighted average grant date fair value of $98.06 per share and generally vest ratably over a four-year period. Additionally, the Company granted approximately 0.2 million shares of performance-based awards whereby the number of shares that ultimately vest are based on the achievement of certain non-market based performance metrics of the Company over a three-year period. The weighted average grant date fair value of these awards was $94.08 per share.

The following weighted average assumptions were used in determining the fair value for options granted in 2015:

Expected dividend yield	1.39%
Expected stock volatility	39.4%
Risk-free interest rate	1.88%
Expected holding period	6.9 years
Grant date fair value	$36.08

Unrecognized compensation expense at September 30, 2015 was $9.8 million and $113.5 million for stock options and unvested restricted stock, respectively, which is expected to be recognized over a weighted average period of 1.3 years and 1.7 years, respectively. Additionally, there was $17.8 million of unrecognized compensation expense relating to the aforementioned non-market based performance-based awards, which is expected to be recognized over a weighted average period of 1.0 years.

The following tables summarize information relating to stock option exercises and restricted stock vesting:

	Nine Months Ended
	September 30,
Exercise of stock options:	2015		2014
Proceeds from stock option exercises	$	68.0	$	131.5
Aggregate intrinsic value	$	64.7	$	107.7
Tax benefit realized upon exercise	$	23.0	$	38.7
Number of shares exercised		1.3		2.8

	Nine Months Ended
	September 30,
Vesting of restricted stock:	2015		2014
Fair value of shares vested	$	111.3	$	92.3
Tax benefit realized upon vesting	$	35.7	$	31.6
Number of shares vested		1.1		1.2

	Nine Months Ended
	September 30,
Vesting of performance-based restricted stock:	2015		2014
Fair value of shares vested	$	43.1	$	38.0
Tax benefit realized upon vesting	$	15.6	$	14.6
Number of shares vested		0.5		0.5