Net Income Per Share

Net income per basic share is computed by dividing net income by the weighted-average number of shares outstanding for the period. Net income per diluted share is computed by dividing net income by the weighted-average number of shares assuming dilution for stock options and restricted stock units. Dilutive shares reflect the potential additional shares that would be outstanding if the dilutive stock options outstanding were exercised and the unvested restricted stock units vested during the period. The computation of net income per share was as follows:



In millions except per share amounts	2017		2016		2015
Net Income	$	1,687	$	2,035	$	1,899
Net income per share—Basic:
Weighted-average common shares	344.1		355.0		367.9
Net income per share—Basic	$	4.90	$	5.73	$	5.16
Net income per share—Diluted:
Weighted-average common shares	344.1		355.0		367.9
Effect of dilutive stock options and restricted stock units	2.7		2.1		2.2
Weighted-average common shares assuming dilution	346.8		357.1		370.1
Net income per share—Diluted	$	4.86	$	5.70	$	5.13

Options that were considered antidilutive were not included in the computation of diluted net income per share. There were no antidilutive options outstanding as of December 31, 2017 and 2016. There were 0.6 million antidilutive options outstanding as of December 31, 2015.