EARNINGS PER SHARE (Tables)

3 Months Ended

Mar. 31, 2017

Earnings Per Share [Abstract]

Schedule of Computation of Basic and Diluted Earnings per Share under Two-Class Method

The following table sets forth the computation of basic and diluted earnings per share under the two-class method (in thousands of dollars, except for share and per share amounts):

	Three Months Ended
	March 31,
	2017			2016
Net earnings attributable to W.W. Grainger, Inc. as reported	$	174,744		$	186,713
Distributed earnings available to participating securities	(546		)	(626		)
Undistributed earnings available to participating securities	(932		)	(1,121		)
Numerator for basic earnings per share – Undistributed and distributed earnings available to common shareholders	173,266			184,966
Undistributed earnings allocated to participating securities	932			1,121
Undistributed earnings reallocated to participating securities	(924		)	(1,114		)
Numerator for diluted earnings per share – Undistributed and distributed earnings available to common shareholders	$	173,274		$	184,973
Denominator for basic earnings per share – weighted average shares	58,720,066			61,668,682
Effect of dilutive securities	482,816			431,119
Denominator for diluted earnings per share – weighted average shares adjusted for dilutive securities	59,202,882			62,099,801
Earnings per share two-class method
Basic	$	2.95		$	3.00
Diluted	$	2.93		$	2.98