SHARE-BASED COMPENSATION (Tables)

3 Months Ended

Mar. 31, 2019

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of Stock Option Activity Under All Stock Plans

A summary of stock option activity under all stock plans for the three months ended March 31, 2019, is presented as follows (in millions, except per share amounts):



	Stock Options Outstanding
	Number Outstanding		Weighted Average Exercise Price Per Share
Balance at December 31, 2018	6.2		$	200.79
Granted	0.3		$	541.37
Exercised	(0.4	)	$	143.80
Forfeited/expired	(0.1	)	$	337.41
Balance at March 31, 2019	6.0		$	219.34

Summary of RSU Activity

A summary of RSUs activity for the three months ended March 31, 2019, is presented as follows (in millions, except per share amounts):



	Shares		Weighted Average Grant Date Fair Value
Unvested balance at December 31, 2018	2.0		$	295.70
Granted	0.7		$	545.52
Vested	(0.7	)	$	250.63
Forfeited	—		$	353.94
Unvested balance at March 31, 2019	2.0		$	394.13

During the three months ended March 31, 2019, approximately 23,000 RSUs were forfeited.

Summary of Share-Based Compensation Expense

The following table summarizes share-based compensation expense for the three months ended March 31, 2019, and 2018 (in millions):



	Three Months Ended March 31,
	2019		2018
Cost of sales - products	$	11.0	$	8.2
Cost of sales - services	4.5		3.9
Total cost of sales	15.5		12.1
Selling, general and administrative	38.6		29.5
Research and development	22.8		16.3
Share-based compensation expense before income taxes	76.9		57.9
Income tax benefit	16.4		12.3
Share-based compensation expense after income taxes	$	60.5	$	45.6

Schedule of Estimated Fair Value of the Option Using Black-Scholes Option Pricing Model, Weighted Average Assumptions

The Black-Scholes option pricing model is used to estimate the fair value of stock options granted under the Company’s stock plans and rights to acquire stock granted under the ESPP. The weighted average estimated fair values of stock options and rights to acquire stock under the ESPP, as well as the weighted average assumptions used in calculating those fair values, were as follows:



	Three Months Ended March 31,
	2019			2018
Stock Options
Risk-free interest rate	2.5		%	2.6		%
Expected term (in years)	4.3			4.3
Expected volatility	31		%	33		%
Fair value at grant date	$	157.64		$	130.51
ESPP
Risk-free interest rate	2.5		%	1.9		%
Expected term (in years)	1.2			1.2
Expected volatility	31		%	32		%
Fair value at grant date	$	154.20		$	124.61