Stock Based Compensation Plans

9 Months Ended

Sep. 30, 2017

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock Based Compensation Plans

6. Stock Based Compensation Plans

The following table provides a summary of option activity:

						Weighted
				Weighted		Average
				Average		Remaining		Aggregate
				Exercise		Contractual		Intrinsic
	Options			Price		Term		Value
Outstanding at December 31, 2016		16.0		$	30.06
Granted		2.1			48.43
Exercised		(1.8	)		22.32
Cancelled		(0.1	)		43.22
Outstanding at September 30, 2017		16.2		$	33.04		5.8	$	260.2
Exercisable at September 30, 2017		10.1		$	25.40		4.2	$	231.8

The following table provides information regarding the intrinsic value of stock options exercised and stock compensation expense related to stock option awards:  

	Three Months Ended				Nine Months Ended
	September 30,		September 30,		September 30,		September 30,
	2017		2016		2017		2016
Intrinsic Value of Stock Options Exercised	$	11.3	$	34.1	$	46.0	$	89.4
Stock Compensation Expense Related to Stock Option Awards	$	2.3	$	1.6	$	13.0	$	12.8
Issued Stock Options		0.3		0.0		2.1		2.0
Weighted Average Fair Value of Stock Options issued (per share)	$	38.02	$	0.0	$	13.12	$	7.58
Fair Value of Stock Options Issued	$	9.6	$	0.0	$	27.0	$	15.4

The following table provides a summary of the assumptions used in the valuation of issued stock options:

	Three Months Ended					Nine Months Ended
	September 30,			September 30,		September 30,			September 30,
	2017			2016		2017			2016
Risk-free interest rate		1.7	%		-		2.0	%		1.7	%
Expected life in years		4.4			-		6.9			6.8
Expected volatility		15.5	%		-		16.7	%		17.0	%
Dividend yield		1.5	%		-		1.4	%		1.5	%