Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2014

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

Summary of granted restricted stock units and stock grants and the weighted average fair value

The following table is a summary of granted restricted stock units, stock units and stock grants and the weighted-average fair value for the 3 years ended 2014, 2013 and 2012: 

	2014		2013		2012
Units granted	130,273		129,620		202,278
Grant date fair value (a)	$	54.91	$	55.21	$	49.31

(a) Weighted-average grant date fair value.

Summary of the status of restricted stock units and stock grants and changes during the year

The following table is a summary of the status of restricted stock units, stock units and stock grants, as of December 31, 2014 and changes during the year.  This table represents only the stock portion of restricted stock units and stock units, per the election on payment discussed in the paragraph above:

Nonvested shares	Shares		Weighted-Average Grant Date Fair Value
Nonvested at January 1, 2014	397,976		$	47.74
Granted	130,273		54.91
Vested	(161,283	)	45.55
Forfeited	(13,067	)	51.53
Nonvested at December 31, 2014	353,899		51.23

Schedule of amount of cash required to settle the payments on restricted stock units

The amount of cash required to settle the payments on restricted stock units is (dollars in millions):

Year	2014		2013		2012
2008 Grant	$	—	$	—	$	1.9
2009 Grant	—		3.0		1.7
2010 Grant	2.3		2.3		0.6
2011 Grant	2.4		2.5		0.7
2012 Grant	2.1		2.2		—
2013 Grant	2.1		—		—

Summary of the performance shares granted and the weighted average fair value

The following table is a summary of the performance shares granted and the weighted-average fair value for the three years ended 2014, 2013 and 2012:

	2014		2013		2012
Units granted (a)	166,244		176,332		185,878
Grant date fair value (b)	$	54.86	$	55.45	$	47.40

(a) Reflects the target payout level.

(b) Weighted-average grant date fair value.

Summary of the status of performance shares and changes during the year

The following table is a summary of the status of performance shares as of December 31, 2014 and changes during the year:

Nonvested shares (a)	Shares		Weighted-Average Grant Date Fair Value
Nonvested at January 1, 2014	344,396		$	51.13
Granted	166,244		54.86
Increase in performance factor	86,558		47.40
Vested	(258,224	)	47.40
Forfeited	(14,744	)	53.30
Nonvested at December 31, 2014	324,230		54.92

(a) Nonvested shares are reflected at target payout level.  The increase or decrease in the number of shares from the target level to the estimated actual payout level is included in the increase for performance factor amounts in the year the award vests.