COVER - USD ($)	12 Months Ended
	Dec. 31, 2023	Feb. 14, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Document Transition Report	false
Entity File Number	1-5684
Entity Registrant Name	W.W. Grainger, Inc.
Entity Incorporation, State or Country Code	IL
Entity Tax Identification Number	36-1150280
Entity Address, Address Line One	100 Grainger Parkway
Entity Address, City or Town	Lake Forest,
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60045-5201
City Area Code	847
Local Phone Number	535-1000
Title of 12(b) Security	Common Stock
Trading Symbol	GWW
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 35,235,880,897
Entity Common Stock, Shares Outstanding		49,173,357
Documents Incorporated by Reference	Portions of the registrant's definitive proxy statement to be filed in connection with the annual meeting of shareholders to be held on April 24, 2024, are incorporated by reference into Part III of this Annual Report on Form 10-K for the fiscal year ended December 31, 2023 (Form 10-K) where indicated. The registrant's definitive proxy statement will be filed with the Securities and Exchange Commission within 120 days after the end of the fiscal year to which this report relates.
Entity Central Index Key	0000277135
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Amendment Flag	false