Share-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2015

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

Summary of Share-Based Compensation

A summary of share-based compensation is as follows:

	For the Three Months Ended March 31,
	2014		2015
Share-based compensation	$	6.5	$	8.0
Tax benefit	2.5		3.1

Schedule of Company Stock Option Transactions

The following table summarizes the transactions of the Company's stock options:

	Stock Options		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (years)
Unexercised options outstanding—December 31, 2014	2.3		$	83.42
Options granted	0.0		197.79
Options exercised	(0.7	)	65.72
Options forfeited	(0.0	)	101.29
Unexercised options outstanding—March 31, 2015	1.6		91.37		2.7
Exercisable at March 31, 2015	1.4		88.60		2.6

Schedule of Company Restricted Stock Unit Transactions

The following table summarizes the transactions of the Company's restricted stock units:

	Restricted Stock		Weighted Average Grant Date Value
Unvested units—December 31, 2014	0.4		$	182.83
Units granted	0.3		197.91
Units vested	(0.1	)	166.56
Units forfeited	(0.0	)	190.65
Unvested units—March 31, 2015	0.6		192.06