STOCK BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2017

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation Expense Resulting from Stock Option Awards, RSUs, PSUs and ESPP

The following table presents the total stock-based compensation expense resulting from stock option awards, RSUs, PSUs, and the ESPP included on the Consolidated Statements of Income:

In millions
	Years Ended December 31,
	2017		2016		2015
Selling, general and administrative - stock option plan	$	14.7	$	17.4	$	18.6
Selling, general and administrative - RSUs		5.2		0.9		1.5
Selling, general and administrative - PSUs		0.2		-		-
Selling, general and administrative - ESPP		1.2		2.2		1.6
Total pre-tax expense	$	21.3	$	20.5	$	21.7

Stock Option Activity

Stock option activity for the year ended December 31, 2017 is summarized as follows:

	Number of Options			Weighted Average Exercise Price per Share
Outstanding at beginning of year		5,468,732		$	96.90
Granted		456,424			82.89
Exercised		(217,922	)		51.54
Forfeited		(188,879	)		111.78
Canceled or expired		(124,938	)		101.94
Outstanding as of December 31, 2017		5,393,417		$	96.91
Exercisable as of December 31, 2017		3,472,994		$	90.55

Intrinsic Value of Options Exercised

The following table sets forth the intrinsic value of options exercised for the years ended December 31:

In millions
	2017		2016		2015
Total exercise intrinsic value of options exercised	$	4.8	$	26.0	$	62.6

Information Related to Outstanding and Exercisable Options

The following table sets forth the information related to outstanding and exercisable options for the years ended December 31:

	2017		2016		2015
Weighted average remaining contractual life of outstanding options (in years)		4.56		5.25		5.70
Total aggregate intrinsic value of outstanding options (in millions)	$	12.8	$	25.1	$	162.4
Weighted average remaining contractual life of exercisable options (in years)		3.87		4.40		4.70
Total aggregate intrinsic value of exercisable options (in millions)	$	12.8	$	25.1	$	130.6

Assumptions Used in Black-Scholes Option Pricing Model

The estimated fair value of stock options at the time of the grant using the Black-Scholes option pricing model was as follows:

	Years Ended December 31,
	2017			2016			2015
Stock options granted (shares)		456,424			1,100,492			1,056,490
Weighted average fair value at grant date	$	19.46		$	20.16		$	22.90
Assumptions:
Expected term (in years)		4.82			4.77			4.79
Expected volatility		22.68	%		18.28	%		16.71	%
Expected dividend yield		—	%		—	%		—	%
Risk free interest rate		1.90	%		1.21	%		1.47	%

Information Related to RSUs

The following table sets forth the information related to RSUs for the years ended December 31:

	2017		2016		2015
Total aggregate intrinsic value of outstanding units (in millions)	$	18.2	$	8.8	$	8.4
Per share weighted average fair value of units granted	$	82.93	$	106.01	$	114.27

Summary of RSU Activity

A summary of the status of our non-vested RSUs and changes during the year ended December 31, 2017, are as follows:

	Number of Units			Weighted Average Grant Date Fair Value
Non-vested at beginning of year		114,838		$	104.22
Granted		210,829			82.93
Vested and Released		(37,225	)		93.86
Forfeited		(21,145	)		93.19
Non-vested as of December 31, 2017		267,297		$	89.74