Earnings Per Share

3 Months Ended

Mar. 31, 2020

Earnings Per Share [Abstract]

Earnings Per Share

Earnings per Share

The denominator for basic and diluted earnings per share for the three months ended March 31, 2020 and 2019 is as follows:

	Three Months Ended   March 31
	2020	2019
Denominator for basic earnings per share – weighted-average shares	252.4	257.1
Effect of dilutive securities – employee stock options, nonvested restricted stock awards and convertible debentures	4.0	5.2
Denominator for diluted earnings per share	256.4	262.3

During the three months ended March 31, 2020 and 2019, weighted-average shares related to certain stock options of 0.9 and 0.2, respectively, were excluded from the denominator for diluted earnings per share because the stock options were anti-dilutive.

During the three months ended March 31, 2020, we issued approximately 1.2 restricted stock units under our stock incentive plans, 0.2 of which vesting is contingent upon us meeting specified annual earnings targets for the three year period of 2020 through 2022. During the three months ended March 31, 2019, we issued approximately 0.5 restricted stock units under our stock incentive plans, 0.2 of which vesting is contingent upon us meeting specified annual earnings targets for the three year period of 2019 through 2021. The contingent restricted stock units have been excluded from the denominator for diluted earnings per share and will be included only if and when the contingency is met.