Share-Based Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2017

Schedule of Changes in Stock Options

	Number of shares (thousands)			Weighted-average exercise price			Weighted-average remaining contractual term (years)		Aggregate intrinsic value (millions)
Option shares outstanding, December 31, 2016		1,350.6		$	34.66
Option shares exercised		(78.2	)		(41.62	)
Option shares outstanding, December 31, 2017		1,272.4		$	34.23			3.4	$	33.5
Option shares exercisable, vested and expected to vest,      December 31, 2017		1,272.4			34.23			3.4	$	33.5

Schedule of Information Related to Stock Option Exercises

The following table presents information related to stock option exercises:

	2017			2016			2015
Total intrinsic value of stock options exercised	$	0.9		$	0.4		$	3.5
Cash proceeds received from stock options exercised	$	3.3		$	0.7		$	6.4
Tax (expense) deduction realized from stock options exercised	$	(0.2	)	$	(0.1	)	$	0.4

Schedule of Restricted Stock and Restricted Stock Units Activity

	Non-Vested Stock Awards
	RSUs						PSUs
	Number of shares (thousands)			Weighted- average fair value at grant date			Number of shares (thousands)			Weighted- average fair value at grant date
December 31, 2016		224.5		$	44.94			290.4		$	40.29
Granted		54.2			47.18			139.4			44.65
Vested		(101.1	)		(46.23	)		(39.7	)		(47.19	)
Forfeited		(6.0	)		(44.23	)		(10.4	)		(43.91	)
December 31, 2017		171.6		$	45.27			379.7		$	41.08

PSUs [Member]

Schedule of Weighted-Average Assumptions

	2017			2016
Weighted-average grant date fair value of market based PSUs granted (dollars per award)	$	43.29		$	37.75
Assumptions
Risk free rate of return		1.5	%		0.8	%
Expected volatility		28.0	%		28.0	%
Expected term (in years)		3.1			2.7
Expected dividend yield		0.0	%		0.0	%