STOCK-BASED COMPENSATION

9 Months Ended

Sep. 30, 2016

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,
	2016		2015		2016		2015
Stock-based compensation cost	$	23.9	$	22.1	$	72.8	$	66.5
Tax benefit	$	7.8	$	7.2	$	23.7	$	21.8

During the first nine months of 2016, the Company granted 0.5 million employee stock options, which had a weighted average grant date fair value of $22.98 per share based on the Black-Scholes option-pricing model. The Company also granted 1.2 million shares of restricted stock in the first nine months of 2016, which had a weighted average grant date fair value of $80.90 per share. Both the employee stock options and restricted stock 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 $76.66 per share.

The following weighted average assumptions were used in determining the fair value for options granted in 2016:

Expected dividend yield	1.83%
Expected stock volatility	32.3%
Risk-free interest rate	1.60%
Expected holding period	6.8 yrs
Grant date fair value	$22.98

Unrecognized compensation expense at September 30, 2016 was $10.4 million and $129.6 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 $14.6 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:	2016		2015
Proceeds from stock option exercises	$	67.7	$	68.0
Aggregate intrinsic value	$	67.8	$	64.7
Tax benefit realized upon exercise	$	23.1	$	23.0
Number of shares exercised		1.4		1.3

	Nine Months Ended
	September 30,
Vesting of restricted stock:	2016		2015
Fair value of shares vested	$	92.8	$	111.3
Tax benefit realized upon vesting	$	29.5	$	35.7
Number of shares vested		1.0		1.1

	Nine Months Ended
	September 30,
Vesting of performance-based restricted stock:	2016		2015
Fair value of shares vested	$	23.6	$	43.1
Tax benefit realized upon vesting	$	8.4	$	15.6
Number of shares vested		0.2		0.5