Computation of Basic/Diluted Earnings Per Common Share

The following table sets forth the computation of basic and diluted earnings per common share (amounts in millions, except per share data):



	For the Three Months Ended September 30,				For the Nine Months Ended September 30,
	2018		2017		2018		2017
Numerator:
Consolidated net income	$	260	$	188	$	1,162	$	858

Denominator:
Denominator for basic earnings per common share—weighted-average common shares outstanding	763		755		761		753
Effect of potential dilutive common shares under the treasury stock method—employee stock options and awards	8		11		10		11
Denominator for basic earnings per common share—weighted-average dilutive common shares outstanding	771		766		771		764

Basic earnings per common share	$	0.34	$	0.25	$	1.53	$	1.14
Diluted earnings per common share	$	0.34	$	0.25	$	1.51	$	1.12

The vesting of certain of our employee-related restricted stock units and options is contingent upon the satisfaction of pre-defined performance measures. The shares underlying these equity awards are included in the weighted-average dilutive common shares only if the performance measures are met as of the end of the reporting period. Approximately 6 million shares are not included in the computation of diluted earnings per share for both the three and nine months ended September 30, 2018, as their underlying performance measures had not yet been met. Approximately 9 million and 8 million shares are not included in the computation of diluted earnings per share for the three and nine months ended September 30, 2017, respectively, as their underlying performance measures had not yet been met.

Potential common shares are not included in the denominator of the diluted earnings per common share calculation when the inclusion of such shares would be anti-dilutive. Therefore, approximately 1 million and 2 million options to purchase shares of common stock were not included in the calculation of diluted earnings per common share for the three and nine months ended September 30, 2018, respectively, and 1 million options to purchase shares of common stock were not included in the calculation of diluted earnings per common share for both the three and nine months ended September 30, 2017, as the effect of their inclusion would be anti-dilutive.