Stock-Based Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2015

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

Schedule of Stock Option Activity

Information related to stock options issued to officers, other employees and directors prior to 2010 under all plans is presented in the following table:

	2015				2014			2013
	Shares		Weighted Average Exercise Price		Shares	Weighted Average Exercise Price		Shares		Weighted Average Exercise Price
Number of shares under option:
Outstanding — beginning of year	97,962		$	16.61	97,962	$	16.61	115,362		$	15.00
Exercised	(13,701	)	11.66		—	—		(17,400	)	5.91
Canceled	—		—		—	—		—		—
Outstanding — end of year	84,261		$	17.42	97,962	$	16.61	97,962		$	16.61
Exercisable — end of year	84,261		$	17.42	97,962	$	16.61	97,962		$	16.61

Additional Information Relating to the Ranges of Options Outstanding

Additional information relating to the ranges of options outstanding at December 31, 2015, is as follows:

	Weighted Average Remaining Contractual Life	Options Outstanding and Exercisable
Range of Exercise Prices per Share		Number Outstanding	Weighted Average Exercise Price per Share
$16.16 - $18.18	0.96	84,261	$	17.42
		84,261	$	17.42

Schedule of Stock-Based Compensation

We recorded stock-based compensation for restricted shares as follows:

	Year Ended December 31,
	2015			2014		2013
	(Amounts in millions)
Stock-based compensation expense	$	34.8		$	42.7	$	35.8
Related income tax benefit	(11.8		)	(14.6)		(12.3)
Net stock-based compensation expense	$	23.0		$	28.1	$	23.5

Information Regarding Restricted Shares

The following table summarizes information regarding Restricted Shares:

	Year Ended December 31, 2015
	Shares		Weighted Average Grant-Date Fair Value
Number of unvested Restricted Shares:
Outstanding — beginning of year	1,856,548		$	52.29
Granted	777,730		53.64
Vested	(962,949	)	42.87
Canceled	(130,486	)	60.82
Outstanding — ending of year	1,540,843		$	58.14