Income per Share

12 Months Ended

Dec. 31, 2019

Basic income per share is based upon the weighted average number of common shares outstanding during the period. Dilutive income per share includes additional common shares that would have been outstanding if potential common shares with a dilutive effect had been issued using the treasury stock method.

A reconciliation of the number of shares used for the basic and diluted income per share calculations is as follows:



	Years ended December 31,
Shares in millions	2019	2018	2017
Basic weighted average common shares outstanding	141	140	141
Stock options, restricted shares, and convertible debt	1	1	—
Diluted weighted average common shares outstanding	142	141	141

For purposes of applying the two-class method in computing income per share, net earnings allocated to participating securities was $1.5 million, or $0.01 per share for fiscal year 2019, $1.8 million, or $0.01 per share for fiscal year 2018, and $3 million, or $0.02 per share for fiscal year 2017. The diluted income per share calculation did not include 1.3 million, 1.5 million, and 2.1 million antidilutive weighted average shares for the years ended December 31, 2019, 2018 and 2017, respectively.