EARNINGS PER SHARE

3 Months Ended

Mar. 31, 2016

The Company uses the two-class method to calculate earnings per share. The numerator for basic and diluted earnings per share is net earnings attributable to shareholders reduced by dividends and undistributed earnings attributable to unvested shares. The denominator for basic earnings per share is the weighted-average shares outstanding during the period. The denominator for diluted earnings per share is the weighted-average number of shares outstanding adjusted for the effect of dilutive stock options and performance share awards.

The following table presents the calculation of basic and diluted earnings per share:



	Three Months Ended March 31,
(Dollars and shares in millions, except per share data)	2016			2015
Basic earnings per share:
Weighted-average shares outstanding	186.6			202.4
Net earnings attributable to shareholders	$	72.7		$	207.4
Dividends and undistributed earnings attributable to unvested shares	(0.3		)	(0.4		)
Net earnings attributable to shareholders used for basic earnings per share calculation	$	72.4		$	207.0
Net earnings attributable to shareholders per share	$	0.39		$	1.02
Diluted earnings per share:
Weighted-average shares outstanding	186.6			202.4
Incremental shares outstanding assuming the exercise/vesting of dilutive stock options/performance shares	0.1			0.5
Weighted-average shares — diluted	186.7			202.9
Net earnings attributable to shareholders	$	72.7		$	207.4
Dividends and undistributed earnings attributable to unvested shares	(0.3		)	(0.4		)
Net earnings attributable to shareholders used for diluted earnings per share calculation	$	72.4		$	207.0
Net earnings attributable to shareholders per share	$	0.39		$	1.02

Potential shares outstanding from all stock-based awards were 3.6 million and 2.9 million as of March 31, 2016 and 2015, respectively, of which 3.5 million and 2.4 million were not included in the diluted earnings per share calculation for the three months ended March 31, 2016 and 2015, respectively.