STOCK-BASED COMPENSATION (Tables)

3 Months Ended

Mar. 31, 2013

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

Stock-based compensation expense was as follows:



	Three Months Ended March 31,
	2013		2012
	($ in millions)
Stock-based compensation	$	2.7	$	1.9
Mark-to-market adjustments	1.8		0.9
Total expense	$	4.5	$	2.8

Schedule of fair value of stock options granted

The fair value of each stock option granted, which typically vests ratably over three years, but not less than one year, was estimated on the date of grant, using the Black-Scholes option-pricing model with the following weighted-average assumptions:



Grant date	2013			2012
Dividend yield	3.44		%	3.65		%
Risk-free interest rate	1.35		%	1.36		%
Expected volatility	43		%	43		%
Expected life (years)	7.0			7.0
Grant fair value (per option)	$	7.05		$	6.55
Exercise price	$	23.28		$	21.92
Shares granted	621,000			480,250

- Definition

Tabular disclosure of components of a stock option or other award plan under which equity-based compensation is awarded to employees, typically comprised of the amount of unearned compensation (deferred compensation cost), compensation expense, and changes in the quantity and fair value of the shares (or other type of equity) granted, exercised, forfeited, and issued and outstanding pertaining to that plan. Disclosure may also include nature and general terms of such arrangements that existed during the period and potential effects of those arrangements on shareholders, effect of compensation cost arising from equity-based payment arrangements on the income statement, method of estimating the fair value of the goods or services received, or the fair value of the equity instruments granted, during the period, cash flow effects resulting from equity-based payment arrangements and, for registrants that accelerate vesting of out of the money share options, reasons for the decision to accelerate.

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