EQUITY (Tables)

12 Months Ended

Dec. 31, 2016

Equity [Abstract]

Total Outstanding Shares

The following table represents total outstanding shares of common stock and treasury stock for the years ended December 31:

(in millions)	Shares of Common Stock	Shares of Treasury Stock		Outstanding Shares
Balance at December 31, 2013	162.8	(20.5	)	142.3
Shares of treasury stock issued	—	1.9		1.9
Repurchase of common stock at an average cost of $49.88	—	(3.3	)	(3.3	)
Balance at December 31, 2014	162.8	(21.9	)	140.9
Shares of treasury stock issued	—	1.3		1.3
Repurchase of common stock at an average cost of $52.50	—	(2.1	)	(2.1	)
Balance at December 31, 2015	162.8	(22.7	)	140.1
Common stock issuance related to Merger	101.7	—		101.7
Shares of treasury stock issued	—	1.7		1.7
Repurchase of common stock at an average cost of $60.78	—	(13.4	)	(13.4	)
Balance at December 31, 2016	264.5	(34.4	)	230.1

Total Stock Based Compensation Expense and the Tax Related Benefit

The following table represents total stock based compensation expense and the tax related benefit for the years ended:

	December 31,
(in millions)	2016		2015		2014
Stock option expense	$	10.6	$	8.1	$	8.8
RSU expense	29.1		16.2		15.4
Total stock based compensation expense	$	39.7	$	24.3	$	24.2
Related deferred income tax benefit	$	10.9	$	7.1	$	6.7

Assumptions Used to Determine Compensation Cost for the Company's Non-qualified Stock Options Issued

The following table sets forth the average assumptions used to determine compensation cost for the Company’s NQSO issued during the years ended:

	December 31,
	2016			2015			2014
Weighted average fair value per share	$	12.78		$	10.87		$	9.41
Expected dividend yield	0.52		%	0.51		%	0.59		%
Risk-free interest rate	1.54		%	1.59		%	1.61		%
Expected volatility	20.8		%	20.3		%	21.6		%
Expected life (years)	6.14			5.68			5.13

Summary of the Non-qualified Stock Option Transactions

The following table summarizes the NQSO transactions for the year ended December 31, 2016:

	Outstanding						Exercisable
(in millions, except per share amounts)	Shares		Weighted Average Exercise Price		Aggregate Intrinsic Value		Shares	Weighted Average Exercise Price		Aggregate Intrinsic Value
December 31, 2015	7.3		$	38.85	$	159.9	5.7	$	36.38	$	139.4
Granted	0.7		57.52
Merger	1.7		26.93
Exercised	(1.3	)	30.73
December 31, 2016	8.4		$	39.22	$	155.9	6.7	$	36.03	$	144.9

Summary of Information about Non-qualified Stock Options Outstanding

The following table summarizes information about NQSO outstanding for the year ended December 31, 2016:

			Outstanding				Exercisable
(in millions, except per share amounts and life)			Number Outstanding at December 31,	Weighted Average Remaining Contractual Life (in years)	Weighted Average Exercise Price		Number Exercisable at December 31,	Weighted Average Exercise Price
Range of
Exercise Prices			2016				2016
5.01	-	10.00	0.3	1.9	$	6.50	0.3	$	6.50
10.01	-	20.00	0.1	1.4	14.39		0.1	14.39
20.01	-	30.00	0.9	2.3	25.68		0.9	25.68
30.01	-	40.00	3.4	4.4	36.49		3.2	36.47
40.01	-	50.00	2.3	5.6	44.11		1.9	43.69
50.01	-	60.00	1.2	8.5	53.58		0.3	52.12
60.01	-	70.00	0.2	9.2	60.74		—	—
			8.4	5.1	$	39.22	6.7	$	36.03

Summary of the Unvested RSU Transactions

The following table summarizes the unvested RSU transactions for the year ended December 31, 2016:

	Unvested Restricted Stock Units
	Shares		Weighted Average Grant Date Fair Value
(in millions, except per share amounts)
Unvested at December 31, 2015	1.1		$	45.82
Granted	0.4		56.40
Merger	1.0		46.64
Vested	(0.5	)	40.06
Forfeited	(0.1	)	50.77
Unvested at December 31, 2016	1.9		$	49.55