W.W. Grainger (GWW) 10-K 27 Feb 14 2013 Q4 Annual report Financial data

DOCUMENT_AND_ENTITY_INFORMATIO

DOCUMENT AND ENTITY INFORMATION (USD $)	12 Months Ended
	Dec. 31, 2013	Jan. 31, 2014	Jun. 30, 2013
Document Information [Line Items]	'	'	'
Entity Registrant Name	'GRAINGER W W INC	'	'
Entity Central Index Key	'0000277135	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Filer Category	'Large Accelerated Filer	'	'
Document Type	'10-K	'	'
Document Period End Date	31-Dec-13	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'Q4	'	'
Amendment Flag	'false	'	'
Entity Common Stock, Shares Outstanding	'	68,797,706	'
Entity Well-known Seasoned Issuer	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Public Float	'	'	$16,677,711,460

CONSOLIDATED_STATEMENTS_OF_EAR

CONSOLIDATED STATEMENTS OF EARNINGS (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net sales	$9,437,758	$8,950,045	$8,078,185
Cost of merchandise sold	5,301,275	5,033,885	4,567,393
Gross profit	4,136,483	3,916,160	3,510,792
Warehousing, marketing and administrative expenses	2,839,629	2,785,035	2,458,363
Operating earnings	1,296,854	1,131,125	1,052,429
Other income and (expense):	'	'	'
Interest income	3,234	2,660	2,068
Interest expense	-13,225	-16,078	-9,091
Equity in net income of unconsolidated entity	0	0	314
Gain on sale of investment in unconsolidated entity	0	0	7,639
Other non-operating income	2,732	1,866	709
Other non-operating expense	-1,996	-1,784	-2,541
Total other income and (expense)	-9,255	-13,336	-902
Earnings before income taxes	1,287,599	1,117,789	1,051,527
Income taxes	479,850	418,940	385,115
Net earnings	807,749	698,849	666,412
Net earnings attributable to noncontrolling interest	10,713	8,968	7,989
Net earnings attributable to W.W. Grainger, Inc.	$797,036	$689,881	$658,423
Earnings per share:	'	'	'
Basic (in dollars per share)	$11.31	$9.71	$9.26
Diluted (in dollars per share)	$11.13	$9.52	$9.07
Weighted average number of shares outstanding:	'	'	'
Basic (in shares)	69,455,507	69,811,881	69,690,854
Diluted (in shares)	70,576,432	71,181,733	71,176,158

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE EARNINGS (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net earnings	$807,749	$698,849	$666,412
Other comprehensive earnings (losses):	'	'	'
Foreign currency translation adjustments, net of tax benefit (expense) of $4,078, $(1,653) and $1,325, respectively	-78,253	7,344	-36,117
Reclassification of cumulative currency translation	0	0	525
Defined postretirement benefit plan, net of tax (expense) benefit of $(20,188), $(47,948) and $18,725, respectively	32,658	75,625	-30,038
Other employment-related benefit plans and derivatives, net of tax (expense) benefit of $(3,080), $2,825 and $89, respectively	5,309	-9,519	-1,932
Total other comprehensive earnings (losses)	-40,286	73,450	-67,562
Comprehensive earnings, net of tax	767,463	772,299	598,850
Less: Comprehensive earnings attributable to noncontrolling interest:	'	'	'
Net earnings	10,713	8,968	7,989
Foreign currency translation adjustments	-15,622	-8,866	4,127
Comprehensive earnings attributable to W.W. Grainger, Inc.	$772,372	$772,197	$586,734

CONSOLIDATED_STATEMENTS_OF_COM1

CONSOLIDATED STATEMENTS OF COMPREHENSIVE EARNINGS (Parentheticals) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Foreign currency translation adjustments, tax benefit (expense)	$4,078	($1,653)	$1,325
Defined postretirement benefit plan tax (expense) benefit	-20,188	-47,948	18,725
Other employment-related benefit plans and derivatives tax (expense) benefit	($3,080)	$2,825	$89

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
CURRENT ASSETS	'	'
Cash and cash equivalents	$430,644	$452,063
Accounts receivable (less allowances for doubtful accounts of $20,096 and $19,449, respectively)	1,101,656	940,020
Inventories - net	1,305,520	1,301,935
Prepaid expenses and other assets	115,331	110,414
Deferred income taxes	75,819	55,967
Prepaid income taxes	15,315	40,241
Total current assets	3,044,285	2,900,640
Land	277,256	265,224
Buildings, structures and improvements	1,259,237	1,224,044
Furniture, fixtures, machinery and equipment	1,404,597	1,271,166
PROPERTY, BUILDINGS AND EQUIPMENT	2,941,090	2,760,434
Less: Accumulated depreciation and amortization	1,732,528	1,615,861
Property, buildings and equipment - net	1,208,562	1,144,573
DEFERRED INCOME TAXES	16,209	51,536
GOODWILL	525,467	543,670
OTHER ASSETS AND INTANGIBLES - NET	471,805	374,179
TOTAL ASSETS	5,266,328	5,014,598
CURRENT LIABILITIES	'	'
Short-term debt	66,857	79,071
Current maturities of long-term debt	30,429	18,525
Trade accounts payable	510,634	428,782
Accrued compensation and benefits	185,905	165,450
Accrued contributions to employees' profit sharing plans	176,800	170,434
Accrued expenses	218,835	204,800
Income taxes payable	6,330	12,941
Total current liabilities	1,195,790	1,080,003
LONG-TERM DEBT (less current maturities)	445,513	467,048
DEFERRED INCOME TAXES AND TAX UNCERTAINTIES	113,585	119,280
EMPLOYMENT-RELATED AND OTHER NONCURRENT LIABILITIES	184,604	230,901
SHAREHOLDERS' EQUITY	'	'
Cumulative Preferred Stock - $5 par value - 12,000,000 shares authorized; none issued or outstanding	0	0
Common Stock - $0.50 par value - 300,000,000 shares authorized; issued 109,659,219 shares	54,830	54,830
Additional contributed capital	893,055	812,573
Retained earnings	5,822,612	5,278,577
Accumulated other comprehensive earnings	28,914	53,578
Treasury stock, at cost – 40,805,281 and 40,180,724 shares, respectively	-3,548,973	-3,175,646
Total W.W. Grainger, Inc. shareholders' equity	3,250,438	3,023,912
Noncontrolling interest	76,398	93,454
Total shareholders' equity	3,326,836	3,117,366
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	$5,266,328	$5,014,598

CONSOLIDATED_STATEMENTS_OF_SHA

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $)	12 Months Ended				12 Months Ended				12 Months Ended				12 Months Ended				12 Months Ended				12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
	Common Stock [Member]	Common Stock [Member]	Common Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Retained Earnings [Member]	Retained Earnings [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Treasury Stock [Member]	Treasury Stock [Member]	Treasury Stock [Member]	Noncontrolling Interest [Member]	Noncontrolling Interest [Member]	Noncontrolling Interest [Member]	Noncontrolling Interest [Member]
Stockholders' Equity Balance	$54,830	$54,830	$54,830	$54,830	$893,055	$812,573	$700,826	$637,686	$5,822,612	$5,278,577	$4,806,110	$4,326,761	$28,914	$53,578	($28,738)	$42,951	($3,548,973)	($3,175,646)	($2,904,243)	($2,857,012)	$76,398	$93,454	$95,494	$82,454
Exercise of stock options	0	0	0	'	4,035	-927	-11,506	'	0	0	0	'	0	0	0	'	64,140	72,502	95,384	'	583	564	459	'
Tax benefits on stock-based compensation awards	0	0	0	'	62,385	60,122	55,824	'	0	0	0	'	0	0	0	'	0	0	0	'	0	0	0	'
Stock option expense	0	0	0	'	17,373	17,898	16,838	'	0	0	0	'	0	0	0	'	0	0	0	'	72	105	294	'
Amortization of other stock-based compensation awards	0	0	0	'	34,049	35,125	33,162	'	0	0	0	'	0	0	0	'	0	0	0	'	0	0	0	'
Settlement and vesting of other stock-based compensation awards	0	0	0	'	-37,851	-31,175	-31,067	'	0	0	0	'	0	0	0	'	-3,709	1,452	8,257	'	0	0	0	'
Director's stock compensation	'	0	'	'	'	30,867	'	'	'	0	'	'	'	0	'	'	'	0	'	'	'	0	'	'
Purchase of treasury stock	0	0	0	'	0	-163	-111	'	0	0	0	'	0	0	0	'	-433,758	-345,357	-150,872	'	-183	-148	-99	'
Purchase of noncontrolling interest - Colombia	0	'	'	'	-51	'	'	'	0	'	'	'	0	'	'	'	0	'	'	'	-9,612	'	'	'
Net earnings	0	0	0	'	0	'	0	'	'	'	'	'	0	0	0	'	0	0	0	'	'	'	'	'
Net earnings attributable to noncontrolling interest	'	'	'	'	'	'	'	'	'	'	'	'	'	'	'	'	'	'	'	'	10,713	8,968	7,989	'
Net earnings attributable to W.W. Grainger, Inc.	'	'	'	'	'	'	'	'	797,036	689,881	658,423	'	'	'	'	'	'	'	'	'	'	'	'	'
Other comprehensive earnings	0	0	0	'	0	0	0	'	0	'	0	'	-24,664	82,316	-71,689	'	0	0	0	'	-15,622	-8,866	4,127	'
Cash dividends paid	0	0	0	'	542	0	0	'	-253,001	-217,414	-179,074	'	0	'	0	'	0	0	0	'	-3,007	-2,663	-1,453	'
Fair value at acquisition	'	'	$0	'	'	'	$0	'	'	'	$0	'	'	'	$0	'	'	'	$0	'	'	'	$1,723	'

STATEMENT_OF_STOCKHOLDERS_EQUI

STATEMENT OF STOCKHOLDERS' EQUITY (Parentheticals) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash dividend paid	$3.59	$3.06	$2.52

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parentheticals) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, except Share data, unless otherwise specified
Allowance for doubtful accounts	$20,096	$19,449
Cumulative preferred stock, par value	$5	$5
Cumulative preferred stock, shares authorized	12,000,000	12,000,000
Cumulative preferred stock, shares issued	0	0
Cumulative preferred stock, shares outstanding	0	0
Common stock, par value	$0.50	$0.50
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	109,659,219	109,659,219
Treasury stock, shares at cost	40,805,281	40,180,724

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
CASH FLOWS FROM OPERATING ACTIVITIES:	'	'	'
Net earnings	$807,749	$698,849	$666,412
Provision for losses on accounts receivable	8,855	9,504	4,761
Deferred income taxes and tax uncertainties	-9,319	12,343	1,666
Depreciation and amortization	180,613	159,049	149,200
Impairment of goodwill and other intangible assets	26,284	4,945	0
(Gains) losses from sales of assets	-22,155	2,609	8,069
Stock-based compensation	55,590	55,500	54,020
Gain on sale of investment in unconsolidated entity	0	0	-7,639
Change in operating assets and liabilities - net of business acquisitions and divestitures:	'	'	'
Accounts receivable	-126,465	-45,953	-85,083
Inventories	-23,636	-14,872	-219,680
Prepaid expenses and other assets	16,873	8,346	-24,228
Trade accounts payable	71,118	-54,314	86,395
Other current liabilities	-707	-58,673	50,718
Current income taxes payable	-4,813	-9,349	16,827
Accrued employment-related benefits cost	9,872	45,795	45,680
Other - net	-3,361	2,416	-1,010
Net cash provided by operating activities	986,498	816,195	746,108
CASH FLOWS FROM INVESTING ACTIVITIES:	'	'	'
Additions to property, buildings and equipment	-272,145	-249,860	-196,942
Proceeds from sales of property, buildings and equipment	26,701	8,530	7,278
Cash paid for business acquisitions, net of cash acquired	-153,915	-64,808	-359,296
Other – net	-68	482	13,892
Net cash used in investing activities	-399,427	-305,656	-535,068
CASH FLOWS FROM FINANCING ACTIVITIES:	'	'	'
Borrowings under lines of credit	144,805	161,160	218,885
Payments against lines of credit	-154,450	-205,006	-194,325
Proceeds from issuance of long-term debt	0	300,000	172,464
Payments of long-term debt and commercial paper	-16,681	-219,950	-179,296
Proceeds from stock options exercised	69,412	72,084	84,337
Excess tax benefits from stock-based compensation	59,984	57,885	52,098
Purchase of treasury stock	-438,473	-340,532	-151,082
Cash dividends paid	-255,466	-220,077	-180,527
Net cash used in financing activities	-590,869	-394,436	-177,446
Exchange rate effect on cash and cash equivalents	-17,621	469	-11,557
NET CHANGE IN CASH AND CASH EQUIVALENTS	-21,419	116,572	22,037
Cash and cash equivalents at beginning of year	452,063	335,491	313,454
Cash and cash equivalents at end of year	430,644	452,063	335,491
Cash payments for interest (net of amounts capitalized)	12,954	16,028	8,996
Cash payments for income taxes	$414,363	$383,698	$312,616

SUMMARY_OF_SIGNIFICANT_ACCOUNT

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2013
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]	'
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	'
	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
	INDUSTRY INFORMATION
	W.W. Grainger, Inc. is a broad-line distributor of maintenance, repair and operating supplies, and other related products and services used by businesses and institutions. In this report, the words “Company” or “Grainger” mean W.W. Grainger, Inc. and its subsidiaries.
	PRINCIPLES OF CONSOLIDATION
	The consolidated financial statements include the accounts of the Company and its subsidiaries. All significant intercompany transactions are eliminated from the consolidated financial statements.
	EQUITY METHOD OF ACCOUNTING FOR INVESTMENTS
	For investments in which the Company owns or controls from 20% to 50% of the voting shares, the equity method of accounting is used. The Company also accounts for investments below 20% using the equity method when significant influence can be exercised over the operating and financial policies of the investee company.
	In October 2011, the Company divested its 49% stake in a joint venture, MRO Korea Co., Ltd., for $12 million, resulting in a pretax gain of $8 million ($5 million after-tax) net of the cumulative foreign currency losses reclassified from Accumulated other comprehensive earnings. The Company previously accounted for this investment under the equity method.
	USE OF ESTIMATES
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, revenues and expenses, and the disclosure of contingent liabilities. Actual results could differ from those estimates.
	FOREIGN CURRENCY TRANSLATION
	The financial statements of the Company's foreign subsidiaries are measured using the local currency as the functional currency. Net exchange gains or losses resulting from the translation of financial statements of foreign operations and related long-term debt and derivative instruments are recorded as a separate component of other comprehensive earnings. See Note 13 to the Consolidated Financial Statements.
	RECLASSIFICATIONS
	Certain amounts in the 2012 and 2011 financial statements, as previously reported, have been reclassified to conform to the 2013 presentation. These reclassifications did not have a material impact on the presentation of the consolidated financial statements.
	REVENUE RECOGNITION
	Revenues recognized include product sales, billings for freight and handling charges and fees earned for services provided. The Company recognizes product sales and billings for freight and handling charges primarily on the date products are shipped to, or picked up by, the customer. In cases where the product is shipped directly to the customer, the company recognizes revenue at the time of shipment on a gross basis. The Company's standard shipping terms are FOB shipping point. On occasion, the Company will negotiate FOB destination terms. These sales are recognized upon delivery to the customer. eCommerce revenues, which accounted for 33% of total 2013 revenues, are recognized on the same terms as revenues through other channels. Fee revenues, which accounted for less than 1% of total 2013 revenues, are recognized after services are completed. Taxes collected from customers and remitted to governmental authorities are presented on a net basis and are not included in revenue.
	COST OF MERCHANDISE SOLD
	Cost of merchandise sold includes product and product-related costs, vendor consideration, freight-out and handling costs. The Company defines handling costs as those costs incurred to fulfill a shipped sales order.
	VENDOR CONSIDERATION
	The Company receives rebates and allowances from its vendors to promote their products. The Company utilizes numerous advertising programs to promote its vendors' products, including catalogs and other printed media, Internet, radio and other marketing programs. Most of these programs relate to multiple vendors, which makes supporting the specific, identifiable and incremental criteria difficult, and would require numerous assumptions and judgments. Based on the inexact nature of trying to track reimbursements to the advertising expenditure for each vendor, the Company treats most vendor advertising allowances as a reduction to Cost of merchandise sold rather than a reduction of operating (advertising) expenses. Rebates earned from vendors that are based on product purchases are capitalized into inventory as part of product purchase price. These rebates are credited to Cost of merchandise sold based on sales. Vendor rebates that are earned based on products sold are credited directly to Cost of merchandise sold.
	ADVERTISING
	Advertising costs are expensed in the year the related advertisement is first presented. Advertising expense was $178 million, $173 million and $145 million for 2013, 2012 and 2011, respectively. Most vendor-provided allowances are classified as an offset to Cost of merchandise sold. For additional information see VENDOR CONSIDERATION above.
	Catalog expense is amortized equally over the life of the catalog, beginning in the month of its distribution. Advertising costs for catalogs that have not been distributed by year-end are capitalized as Prepaid expenses. Amounts included in Prepaid expenses at December 31, 2013 and 2012, were $36 million and $46 million, respectively.
	WAREHOUSING, MARKETING AND ADMINISTRATIVE EXPENSES
	Included in this category are purchasing, branch operations, information services, and marketing and selling expenses, as well as other types of general and administrative costs.
	STOCK INCENTIVE PLANS
	The Company measures all share-based payments using fair-value-based methods and records compensation expense related to these payments over the vesting period. See Note 11 to the Consolidated Financial Statements.
	INCOME TAXES
	Income taxes are recognized during the year in which transactions enter into the determination of financial statement income, with deferred taxes being provided for temporary differences between financial and tax reporting. The Company recognizes in the financial statements a provision for tax uncertainties, resulting from application of complex tax regulations in multiple tax jurisdictions. See Note 14 to the Consolidated Financial Statements.
	OTHER COMPREHENSIVE EARNINGS (LOSSES)
	The Company's Other comprehensive earnings (losses) include foreign currency translation adjustments, changes in fair value of derivatives designated as hedges and unrecognized gains (losses) on postretirement and other employment-related benefit plans. See Note 13 to the Consolidated Financial Statements.
	CASH AND CASH EQUIVALENTS
	The Company considers investments in highly liquid debt instruments, purchased with an original maturity of 90 days or less, to be cash equivalents.
	CONCENTRATION OF CREDIT RISK
	The Company places temporary cash investments with institutions of high credit quality and, by policy, limits the amount of credit exposure to any one institution.
	The Company has a broad customer base representing many diverse industries doing business in all regions of the United States, Canada, Europe, Asia and Latin America. Consequently, no significant concentration of credit risk is considered to exist.
	ALLOWANCE FOR DOUBTFUL ACCOUNTS
	The Company establishes reserves for customer accounts that are potentially uncollectible. The method used to estimate the allowances is based on several factors, including the age of the receivables and the historical ratio of actual write-offs to the age of the receivables. These analyses also take into consideration economic conditions that may have an impact on a specific industry, group of customers or a specific customer.
	INVENTORIES
	Inventories are valued at the lower of cost or market. Cost is determined primarily by the last-in, first-out (LIFO) method, which accounts for approximately 59% of total inventory. For the remaining inventory, cost is determined by the first-in, first-out (FIFO) method.
	PROPERTY, BUILDINGS AND EQUIPMENT
	Property, buildings and equipment are valued at cost. For financial statement purposes, depreciation and amortization are provided in amounts sufficient to relate the cost of depreciable assets to operations over their estimated service lives, principally on the declining-balance and sum-of-the-years-digits depreciation methods. The Company's international businesses record depreciation expense primarily on a straight-line basis. The principal estimated useful lives for determining depreciation are as follows:
	Buildings, structures and improvements	10 to 30 years
	Furniture, fixtures, machinery and equipment	3 to 10 years
	Improvements to leased property are amortized over the initial terms of the respective leases or the estimated service lives of the improvements, whichever is shorter.
	The Company capitalized interest costs of $1 million in each of years 2013, 2012 and 2011.
	LONG-LIVED ASSETS
	The carrying value of long-lived assets is evaluated whenever events or changes in circumstances indicate that the carrying value of the asset may be impaired. An impairment loss is recognized when estimated undiscounted future cash flows resulting from use of the asset, including disposition, are less than the carrying value of the asset. Impairment is measured as the amount by which the carrying amount exceeds the fair value.
	The Company recognized impairment charges of $0.4 million, $2 million and $8 million in 2013, 2012 and 2011, respectively, included in Warehousing, marketing and administrative expenses, to reduce the carrying value of certain long-lived assets to their estimated fair value pursuant to impairment indicators for property currently held for sale, lease terminations, idle assets and branch closures.
	CAPITALIZED SOFTWARE
	The Company capitalizes certain costs related to the purchase and development of internal-use software. Amortization of capitalized software is on a straight-line basis over three and five years. Amortization begins when the software is available for its intended use. Amortization expense was $23 million, $16 million and $19 million for the years ended December 31, 2013, 2012 and 2011, respectively. Capitalized software was $107 million and $72 million at December 31, 2013 and 2012, respectively and are included in Other assets and intangibles - net on the Consolidated Balance Sheets.
	GOODWILL AND OTHER INTANGIBLES
	Goodwill is recognized as the excess cost of an acquired entity over the net amount assigned to assets acquired and liabilities assumed. Goodwill is not amortized, but rather tested for impairment on an annual basis and more often if circumstances require. Impairment losses are recognized whenever the implied fair value of goodwill is less than its carrying value.
	The Company recognizes an acquired intangible apart from goodwill whenever the intangible arises from contractual or other legal rights, or whenever it can be separated or divided from the acquired entity and sold, transferred, licensed, rented or exchanged, either individually or in combination with a related contract, asset or liability. Such intangibles are amortized over their estimated useful lives unless the estimated useful life is determined to be indefinite. Amortizable intangible assets are being amortized primarily over useful lives of three to 22 years. The straight-line method of amortization is used as it has been determined to approximate customer attrition patterns and the use pattern of the assets. Impairment losses are recognized if the carrying amount of an intangible, subject to amortization, is not recoverable from expected future cash flows and its carrying amount exceeds its fair value.
	The Company also maintains intangible assets with indefinite lives, which are not amortized. These intangibles are tested for impairment on an annual basis and more often if circumstances require. Impairment losses are recognized whenever the implied fair value of these assets is less than their carrying value. See Note 2 and Note 3 to the Consolidated Financial Statements.
	FAIR VALUE OF FINANCIAL INSTRUMENTS
	The carrying amounts of cash and cash equivalents, receivables, and accounts payable approximate fair value due to the short-term nature of these financial instruments. The carrying value of long-term debt also approximates fair value due to the variable interest rates. The fair value of the Company's qualifying derivative instruments is recorded in the Consolidated Balance Sheets and is discussed in more detail in Note 8 to the Consolidated Financial Statements.
	DERIVATIVE INSTRUMENTS AND HEDGING
	The Company uses derivative financial instruments to manage exposures to fluctuations in interest rates and foreign currency exchange rates. The Company does not enter into derivative financial instruments for trading or speculative purposes. All derivative instruments are recognized as either assets or liabilities in the balance sheet at their fair value. Changes in the fair value of derivatives are recognized in net earnings or other comprehensive earnings (losses) depending on whether the derivative is designated as part of a qualifying hedging relationship. The ineffective portion of a qualifying hedging derivative and derivatives not designated as a hedge are recognized immediately in earnings. Instruments that do not qualify for hedge accounting are marked to market with the change recognized in current period earnings. See Note 8 and Note 13 to the Consolidated Financial Statements for additional information on the Company's derivative activities.
	INSURANCE RESERVES
	The Company purchases insurance for catastrophic exposures and those risks required to be insured by law. It also retains a significant portion of the risk of certain losses related to workers' compensation, general liability and property losses through the utilization of high deductibles and self-insured retentions. Reserves for these potential losses are based on an external analysis of the Company's historical claims results and other actuarial assumptions.
	WARRANTY RESERVES
	The Company generally warrants the products it sells against defects for one year. For a significant portion of warranty claims, the manufacturer of the product is responsible for expenses. For warranty expenses not covered by the manufacturer, the Company provides a reserve for future costs based primarily on historical experience. Warranty reserves were $4 million at December 31, 2013 and 2012.
NEW ACCOUNTING STANDARDS
In February 2013, the Financial Accounting Standards Board issued Accounting Standards Update (ASU) 2013-02, Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income. Under ASU 2013-02, an entity is required to provide information about the amounts reclassified out of accumulated other comprehensive income (AOCI) by component. In addition, an entity is required to present, either on the face of the financial statements or in the notes, significant amounts reclassified out of AOCI by the respective line items of net income, but only if the amount reclassified is required to be reclassified in its entirety in the same reporting period. For amounts that are not required to be reclassified in their entirety to net income, an entity is required to cross-reference to other disclosures that provide details about those amounts. ASU 2013-02 does not change the current requirements for reporting net income or other comprehensive income in the financial statements. ASU 2013-02 is effective for interim and annual periods beginning after December 15, 2012 and early adoption is permitted. The Company adopted ASU 2013-02 in the first quarter of 2013. The adoption of ASU 2013-02 did not have a material impact on the consolidated financial statements.
In July 2013, the Financial Accounting Standards Board issued ASU 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. The guidance requires the presentation of certain unrecognized tax benefits as reductions to deferred tax assets rather than as liabilities in the condensed consolidated balance sheets when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. The amendments will be effective for interim and annual periods beginning after December 15, 2013. Early adoption and retrospective application are permitted. The Company does not expect the adoption of ASU 2013-11 to have a material impact on the Company’s consolidated financial statements.

BUSINESS_ACQUISITIONS

BUSINESS ACQUISITIONS	12 Months Ended
	Dec. 31, 2013
Notes to Financial Statements [Abstract]	'
BUSINESS ACQUISITIONS	'
	BUSINESS ACQUISITIONS
	On December 3, 2013, the Company acquired Safety Solutions, Inc. With 2012 sales of $63 million, Safety Solutions is a distributor of safety footwear, supplies and services with a strong focus on the manufacturing sector. The Company paid $30 million for the Safety Solutions acquisition, less cash acquired. Goodwill and intangibles recorded totaled approximately $21 million. The purchase price allocation has not been finalized and is subject to change as the Company obtains additional information during the measurement period related to the valuation of the acquired assets and liabilities.
	On August 23, 2013, the Company acquired E&R Industrial Sales, Inc. With 2012 sales of approximately $180 million, E&R Industrial is a distributor of metalworking, production supplies and MRO materials to manufacturers and industrial customers across the Midwest and Eastern United States. The Company paid $116 million for the E&R Industrial acquisition, less cash acquired. Goodwill and intangibles recorded totaled approximately $80 million. The purchase price allocation has not been finalized and is subject to change as the Company obtains additional information during the measurement period related to the valuation of the acquired assets and liabilities.
	On April 18, 2013, the Company acquired the remaining noncontrolling interest in Grainger Colombia for $10 million.
	During 2012, the Company acquired Techni-Tool, Inc., for $43 million, less cash acquired. Goodwill recorded totaled $10 million. Purchased identified intangible assets totaled $20 million. Acquired intangibles primarily consist of customer relationships, trademarks and trade names. The customer relationships are amortized on a straight-line basis over 13 years and the trade names are amortized on a straight-line basis over 3 years. The acquired trademark is classified as an indefinite-lived intangible asset.
	During 2012, the Company acquired AnFreixo S.A., for $25 million, less cash acquired. Goodwill recorded totaled $11 million. Purchased identified intangible assets totaled $9 million. Acquired intangibles primarily consist of customer relationships and a supply contract. The 2 customer relationship intangible assets are amortized on a straight-line basis over 11 years and 15 years, respectively. The supply contract intangible is amortized on a straight-line basis over 4 years.
	During 2011, the Company acquired Fabory for $358 million, less cash acquired. Goodwill recorded totaled $140 million. Purchased identified intangible assets totaled $131 million. Acquired intangibles primarily consist of customer relationships and trade names. The customer relationships are amortized on a straight-line basis over 22 years. The indefinite-lived intangible is related to the Fabory trade name and trademarks.
	The results of these acquisitions are included in the Company's consolidated results from the respective dates of acquisition. Due to the immaterial nature of these transactions, both individually and in the aggregate, disclosures of amounts assigned to the acquired assets and assumed liabilities and pro forma results of operations were not considered necessary.

GOODWILL_AND_OTHER_INTANGIBLE_

GOODWILL AND OTHER INTANGIBLE ASSETS	12 Months Ended
	Dec. 31, 2013
Notes to Financial Statements [Abstract]	'
GOODWILL AND OTHER INTANGIBLE ASSETS	'
	GOODWILL AND OTHER INTANGIBLE ASSETS
	Goodwill is recognized as the excess cost of an acquired entity over the amount assigned to assets acquired and liabilities assumed. Goodwill is not amortized, but rather tested for impairment on an annual basis and more often if circumstances require. Impairment losses are recognized whenever the implied fair value of goodwill is less than its carrying value.
	The changes in the carrying amount of goodwill by segment are as follows (in thousands of dollars):
			United States				Canada				Other Businesses				Total
	Balance at January 1, 2012		$	151,231			$	150,645			$	207,307			$	509,183
	Acquisitions		23,385				—				12,466				35,851
	Purchase price adjustments		—				—				4,523				4,523
	Impairment		(4,177		)		—				—				(4,177		)
	Translation		—				4,130				(5,840		)		(1,710		)
	Balance at December 31, 2012		170,439				154,775				218,456				543,670
	Acquisitions		35,820				—				—				35,820
	Purchase price adjustments		(12,900		)		—				2,067				(10,833		)
	Impairment		(12,861		)		—				(11,260		)		(24,121		)
	Translation		—				(10,187		)		(8,882		)		(19,069		)
	Balance at December 31, 2013		$	180,498			$	144,588			$	200,381			$	525,467
	Business acquisitions result in the recording of goodwill and identified intangible assets which affect the amount of amortization expense and possible impairment write-downs that may occur in future periods. Grainger annually reviews goodwill and intangible assets with indefinite lives for impairment in the fourth quarter and when events or changes in circumstances indicate the carrying value of these assets might exceed their current fair values. Grainger tests for goodwill impairment at the reporting unit level and performs a qualitative assessment of factors such as a reporting unit's current performance and overall economic factors to determine if it is more likely than not that the goodwill might be impaired and whether it is necessary to perform the two-step quantitative goodwill impairment test. In the two-step test, Grainger compares the carrying value of assets of the reporting unit to its calculated fair value. If the carrying value of assets of the reporting unit exceeds its calculated fair value, the second step is performed, where the implied fair value of goodwill is compared to the carrying value of assets, to determine the amount of impairment.
	The fair value of reporting units is calculated using primarily the discounted cash flow (DCF) method and incorporating value indicators from a market approach to evaluate the reasonableness of the resulting fair values. The DCF method incorporates various assumptions including the amount and timing of future expected cash flows, including revenues, gross margins, operating expenses, capital expenditures and working capital based on operational budgets, long range strategic plans and other estimates. The terminal value growth rate is used to calculate the value of cash flows beyond the last projected period and reflects management’s best estimates for perpetual growth for the reporting units. Estimates of market-participant risk-adjusted weighted average cost of capital (WACC) are used as a basis for determining the discount rates to apply to the reporting units’ future expected cash flows and terminal value.
	Grainger completed the annual impairment testing using the qualitative approach for seven reporting units and the two-step quantitative test for four of these reporting units during the fourth quarter. For two of these reporting units, Grainger Lighting Services (GLS) and Grainger Brazil (GB), the two-step quantitative test indicated that the carrying value of assets exceeded the calculated fair value and step two impairment calculations were required. As part of the review of the strategic plans for GLS during the fourth quarter, Grainger evaluated the impact of planned changes to the business model and level of investment in the business. Grainger’s estimates of future projected sales growth, operating earnings, and cash flows were revised to reflect lower estimates for new customers and projects.  As a result of the lower projections, Grainger recognized impairment charges of $13 million on the GLS reporting unit.
	During the fourth quarter, management provided strategic plans which included changes to the business model and level of investment required for GB based on insights gained from owning the business since the acquisition in the second quarter of 2012. Grainger’s assumptions were revised to reflect changes related to realization of expected deal synergies and anticipated short-term and long-term operating results of GB that were different from pre-acquisition projections. As a result of the lower performance expectations, Grainger’s estimates for future projected sales growth, operating earnings, and cash flows were revised accordingly. These lowered expectations, as well as an increase in relevant risk factors that increased the discount rate used in the calculations, resulted in the calculated fair value of GB being lower than the carrying value of assets in the step one analysis.  As a result of the completion of step two, Grainger recognized a goodwill impairment charge of $11 million.
	For the two other reporting units, the fair values calculated in the step one analysis exceeded the carrying value of assets and therefore the step two calculation was not required. Fabory, with $134 million of goodwill, had a calculated fair value which exceeded the carrying value of assets by 17%. The risk of potential failure of step one of the impairment test for Fabory in future reporting periods is highly dependent upon key assumptions including the amount and timing of future expected cash flows, sales growth rates, gross margins, capital expenditures, discount rates and estimates of market-participant risk-adjusted WACC. These assumptions require considerable management judgment and are subject to uncertainty. Changes in assumptions regarding the future performance and a continued unfavorable economic environment in Europe may also have a significant impact on cash flows in the future. Given the sensitivity of the calculated fair value to changes in these key assumptions, Grainger may be required to recognize an impairment for Fabory’s goodwill in the future due to changes in market conditions or other factors related to these key assumptions.
	Grainger Colombia, with $14 million of goodwill, had a calculated fair value which exceeded the carrying value of assets by 26% as of the test date.
	Intangible assets included in Other assets and intangibles - net in the Consolidated Balance Sheets were comprised of the following (in thousands of dollars):
		As of December 31,
		2013												2012
		Gross carrying amount				Accumulated amortization				Net carrying amount				Gross carrying amount				Accumulated amortization		Net carrying amount
	Amortized customer lists and relationships	$	350,760			$	134,889			$	215,871			$	279,068			$	124,137	$	154,931
	Amortized trademarks, trade names and other	38,670				23,919				14,751				34,907				21,885		13,022
	Non-amortized trade names	72,790				—				72,790				74,782				—		74,782
	Total intangible assets	$	462,220			$	158,808			$	303,412			$	388,757			$	146,022	$	242,735
	The estimated useful lives for acquired intangibles are primarily as follows:
	Customer lists and relationships	6 to 22 years
	Amortized trademarks, trade names and other	3 to 17 years
	Amortization expense recognized on intangible assets was $15 million, $13 million and $12 million for the years ended December 31, 2013, 2012 and 2011, respectively, and is included in Warehousing, marketing and administrative expenses on the Consolidated Statement of Earnings.
	Estimated amortization expense for future periods is as follows (in thousands of dollars):
	Year		Expense
	2014		$	20,257
	2015		20,057
	2016		18,587
	2017		17,630
	2018		16,580
	Thereafter		137,511

ALLOWANCE_FOR_DOUBTFUL_ACCOUNT

ALLOWANCE FOR DOUBTFUL ACCOUNTS	12 Months Ended
	Dec. 31, 2013
Notes to Financial Statements [Abstract]	'
ALLOWANCE FOR DOUBTFUL ACCOUNTS	'
	ALLOWANCE FOR DOUBTFUL ACCOUNTS
	The following table shows the activity in the allowance for doubtful accounts (in thousands of dollars):
		For the Years Ended December 31,
		2013			2012
	Balance at beginning of period	$	19,449		$	18,801
	Provision for uncollectible accounts	8,855			9,504
	Write-off of uncollectible accounts, net of recoveries	(7,942		)	(9,100		)
	Business acquisitions, foreign currency and other	(266		)	244
	Balance at end of period	$	20,096		$	19,449

INVENTORIES

INVENTORIES	12 Months Ended
	Dec. 31, 2013
Notes to Financial Statements [Abstract]	'
INVENTORIES	'
	INVENTORIES
	Inventories primarily consist of merchandise purchased for resale. Inventories would have been $388 million and $376 million higher than reported at December 31, 2013 and 2012, respectively, if the FIFO method of inventory accounting had been used for all Company inventories. Net earnings would have increased by $8 million, $13 million and $11 million for the years ended December 31, 2013, 2012 and 2011, respectively, using the FIFO method of accounting. Inventory values using the FIFO method of accounting approximate replacement cost. The Company provides reserves for excess and obsolete inventory. The reserve balance was $134 million and $133 million as of December 31, 2013 and 2012, respectively.

SHORTTERM_DEBT

SHORT-TERM DEBT	12 Months Ended
	Dec. 31, 2013
Notes to Financial Statements [Abstract]	'
SHORT-TERM DEBT	'
	SHORT-TERM DEBT
	Lines of Credit
	Foreign subsidiaries utilize lines of credit to meet business growth and operating needs. The outstanding balances were $67 million and $79 million, as of December 31, 2013 and 2012, respectively. The maximum month-end balance outstanding during the year was $77 million and $79 million for 2013 and 2012, respectively. The weighted average interest rates were 4.96% and 5.16% during 2013 and 2012, respectively. As of December 31, 2013 and 2012, the weighted average interest rates were 5.02% and 5.07%, respectively. The Company had $109 million and $138 million of uncommitted lines of credit denominated in foreign currencies at December 31, 2013 and 2012, respectively.
	The Company had a committed line of credit of $600 million in 2013 and $400 million in 2012 for which the Company paid a commitment fee of 0.06% and 0.10% as of December 31, 2013 and 2012, respectively. This line of credit supports the issuance of commercial paper. The current line is due to expire in August 2018. There were no borrowings under this committed line of credit.
	Letters of Credit
	The Company had $26 million and $21 million of letters of credit at December 31, 2013 and 2012, respectively, primarily related to the Company's insurance program. Letters of credit were also issued to facilitate the purchase of products. These issued amounts were $3 million and $4 million at December 31, 2013 and 2012, respectively. Letters of credit issued by the Company's international businesses were immaterial.

LONGTERM_DEBT

LONG-TERM DEBT	12 Months Ended
	Dec. 31, 2013
Notes to Financial Statements [Abstract]	'
LONG-TERM DEBT	'
	LONG-TERM DEBT
	Long-term debt consisted of the following (in thousands of dollars):
		As of December 31,
		2013			2012
	Bank term loan	$	292,500		$	300,000
	Euro-denominated bank term loan	158,067			158,328
	Other	25,375			27,245
	Less current maturities	(30,429		)	(18,525		)
		$	445,513		$	467,048
	Bank Term Loan
	In May 2012, the Company entered into a $300 million, unsecured bank term loan, which matures in November 2016. The proceeds were used to refinance existing debt and for general corporate purposes. The Company may prepay the loan in whole or in part at its option. Quarterly principal payments began in August 2013.
	At the election of the Company, the term loan shall bear interest at the Base Rate plus the Applicable Margin or the LIBOR Rate plus the Applicable Margin as defined within the term loan agreement. At December 31, 2013, the Company had elected a one-month LIBOR Interest Period. The weighted average interest rate during the year was 1.19%.
	Euro-Denominated Bank Term Loan
	In August 2011, the Company entered into a €120 million, unsecured bank term loan in connection with the acquisition of Fabory, maturing in August 2016. The Company, at its option, may prepay this term loan in whole or in part. Payments of €2.5 million are due semi-annually, beginning February 28, 2013, with the remaining balance due at maturity. The weighted average interest rate paid during the year was 1.70%. The weighted average interest rate includes inputs from variable rates and an interest rate swap. See Note 8 to the Consolidated Financial Statements.
	The scheduled aggregate principal payments related to long-term debt are due as follows (in thousands of dollars):
	Year		Payment Amount
	2014		$	30,429
	2015		35,124
	2016		393,886
	2017		1,392
	2018		1,106
	Thereafter		14,005
	The Company's debt instruments include only standard affirmative and negative covenants for debt instruments of similar amounts and structure. The Company's debt instruments do not contain financial or performance covenants restrictive to the business of the Company, reflecting its strong financial position. The Company is in compliance with all debt covenants for the year ended December 31, 2013.

DERIVATIVE_INSTRUMENTS

DERIVATIVE INSTRUMENTS	12 Months Ended
	Dec. 31, 2013
Notes to Financial Statements [Abstract]	'
DERIVATIVE INSTRUMENTS	'
	DERIVATIVE INSTRUMENTS
	The fair values of the Company's derivative instruments are determined by using quoted market forward rates (Level 2 inputs) and reflect the present value of the amount that the Company would pay for contracts involving the same notional amounts and maturity dates.
	During the fourth quarter of 2011, the Company entered into a pay-fixed / receive floating interest rate swap with a notional value of €60 million maturing in August 2016 to partially hedge the future interest expense of the euro-denominated term loan entered into to fund a portion of the Fabory acquisition. The swap is accounted for as a cash flow hedge. The effective portion of the changes in fair value of the derivative is reported as a component of other comprehensive earnings (losses) and reclassified to net income when the hedged transaction affects earnings. The value of the interest-rate swap, included on the Company's balance sheet under Employment-related and other noncurrent liabilities, was $3 million and $4 million as of December 31, 2013 and 2012, respectively.
	During the fourth quarter of 2010, the Company entered into multiple foreign currency forward contracts with a total notional value of C$160 million maturing in September 2014. These forward contracts are designated and qualify as a hedge of an intercompany net investment in the Company's Canadian subsidiary. The Company uses the forward method of assessing hedge effectiveness for derivatives designated as hedging instruments of a net investment in a foreign subsidiary and all changes in fair value of the derivatives are reported as a component of other comprehensive earnings (losses), net of tax effects, as long as specific hedge accounting criteria are met. As of December 31, 2013, the foreign currency forward contracts were included on the Company's balance sheet under Prepaid expenses and other assets for $1 million. As of December 31, 2012, the foreign currency forward contracts were included on the Company's balance sheet under Employment-related and other noncurrent liabilities for $8 million.
	Other foreign currency forward contracts entered into during the current and prior periods to hedge non-functional currency-denominated intercompany note receivables and forecasted U.S. dollar-denominated obligations by foreign subsidiaries of the Company were not material.
	See Note 1 to the Consolidated Financial Statements for a description of the Company's Accounting Policy regarding derivative instruments and Note 13 to the Consolidated Financial Statements for additional information.

EMPLOYEE_BENEFITS

EMPLOYEE BENEFITS	12 Months Ended
	Dec. 31, 2013
Notes to Financial Statements [Abstract]	'
EMPLOYEE BENEFITS	'
	EMPLOYEE BENEFITS
	The Company provides various retirement benefits to eligible employees, including contributions to defined contribution plans, pension benefits associated with defined benefit plans, postretirement medical benefits and other benefits. Eligibility requirements and benefit levels vary depending on employee location. Various foreign benefit plans cover employees in accordance with local legal requirements.
	Defined Contribution Plans
	A majority of the Company's U.S. employees are covered by a noncontributory profit sharing plan. This plan provides for annual employer contributions based upon a formula related primarily to earnings before federal income taxes, limited to a percentage of the total eligible compensation paid to eligible employees. The annual contribution is limited to a minimum of 8% and a maximum of 18% of total eligible compensation paid to eligible employees. The profit sharing plan expense was $173 million, $165 million and $156 million for 2013, 2012 and 2011, respectively.
	The Company sponsors additional defined contribution plans available to certain U.S. and foreign employees for which contributions are paid by the Company and participating employees. The expense associated with these defined contribution plans totaled $12 million for each of the years ended December 31, 2013 and 2012 and $9 million for 2011.
	Defined Benefit Plans and Other Retirement Plans
	The Company sponsors a defined benefit plan which provides pension benefits for certain employees in the Netherlands. The annual pension benefit is based on 1.75 percent of a career average pay and years of service. The plan is insured and accordingly, all risks with respect to investments, mortality and longevity are covered by an insurance company. The assets of the plan are invested in a separate account with the insurer. A December 31 measurement date is utilized to value plan assets and obligations. Funding of the plan takes place through single premiums for obligations regarding future service years. As of December 31, 2013 and 2012, the pension plan was in an overfunded position with a net pension asset of $5 million and $6 million, respectively. The expense related to this plan was not significant to the Company in the past three years.
	In certain countries, pension contributions are made to government-sponsored social security pension plans in accordance with local legal requirements. For these plans, the Company has no continuing obligations other than the payment of contributions. The cost of these programs is not significant to the Company.
	Executive Death Benefit Plan
	The Executive Death Benefit Plan provides one of three potential benefits: a supplemental income benefit (SIB), an executive death benefit (EDB) or a postretirement payment. The SIB provides income continuation at 50% of total compensation, payable for ten years to the beneficiary of a participant if that participant dies while employed by the Company. The EDB provides an after-tax lump sum payment of one-time final total compensation to the beneficiary of a participant who dies after retirement. In addition, pre-2008 participants may elect to receive a reduced postretirement payment instead of the EDB. Effective January 1, 2010, the plan is not available to new participants.
	The net periodic benefits costs charged to operating expenses were $0.8 million in year 2013 and $1 million in 2012 and 2011. The net loss (gain) recognized in Accumulated other comprehensive earnings (AOCE) was $(1) million and $0.2 million as of December 31, 2013, and 2012, respectively. The plan benefits are paid as they come due from the general assets of the Company. The plan benefit obligation was $15 million as of December 31, 2013, and $17 million as of December 31, 2012.
	Postretirement Benefits
	The Company has a postretirement healthcare benefits plan that provides coverage for a majority of its United States employees hired prior to January 1, 2013, and their dependents should they elect to maintain such coverage upon retirement. Covered employees become eligible for participation when they qualify for retirement while working for the Company. Participation in the plan is voluntary and requires participants to make contributions toward the cost of the plan, as determined by the Company.
	During the fourth quarter 2012, the Company implemented plan design changes effective January 1, 2013. Employees hired after January 1, 2013 are not eligible to receive retiree health benefits. Active participants in the plan as of December 31, 2012 will remain eligible for retiree health benefits with the employee contribution structure modified for certain employees based on retirement eligibility. As a result of this plan amendment, the Company's postretirement benefit obligation declined $84 million as of December 31, 2012.
	During the fourth quarter 2012, the Company also implemented an Employer Group Waiver Plan (EGWP) and a secondary supplemental "wrap-around" plan for its Medicare eligible retiree medical plan participants and no longer applied for the Part D Retiree Drug Subsidy (RDS) effective January 1, 2013. The EGWP program does not alter the benefits expected to be provided to the plan participants and is expected to increase the level of Medicare subsidies that will offset plan costs. Accordingly, the event was recognized as an actuarial gain for the year ended December 31, 2012. As a result of this change, the Company's postretirement benefit obligation declined $19 million as of December 31, 2012.
	The “Medicare Prescription Drug, Improvement and Modernization Act of 2003” provides a federal subsidy to retiree healthcare benefit plan sponsors that provide a prescription drug benefit that is at least actuarially equivalent to that provided by Medicare. As a result of the subsidy, the Company's postretirement benefit obligation reflected a reduction of $68 million as of December 31, 2011. As a result of the implementation of the EGWP program, the benefit obligation was no longer reduced by Part D RDS as of December 31, 2012. The subsidy reduced net periodic benefits costs by approximately $9 million and $7 million for the years ended December 31, 2012 and 2011, respectively.
	The net periodic benefits costs charged to operating expenses, which were valued with a measurement date of January 1 for each year, consisted of the following components (in thousands of dollars):
		For the Years Ended December 31,
		2013				2012				2011
	Service cost	$	10,589			$	20,058			$	15,762
	Interest cost	8,938				12,810				13,352
	Expected return on assets	(7,076		)		(6,210		)		(5,790		)
	Amortization of prior service credit	(7,412		)		(495		)		(495		)
	Amortization of transition asset	(143		)		(143		)		(143		)
	Amortization of unrecognized losses	3,724				4,827				3,269
	Net periodic benefits costs	$	8,620			$	30,847			$	25,955
	The Company has elected to amortize the amount of net unrecognized gains (losses) over a period equal to the average remaining service period for active plan participants expected to retire and receive benefits of approximately 15.6 years for 2013.
	Reconciliations of the beginning and ending balances of the postretirement benefit obligation, which is calculated using a December 31 measurement date, the fair value of plan assets and the funded status of the benefit obligation follow (in thousands of dollars):
		2013				2012
	Benefit obligation at beginning of year	$	246,087			$	328,912
	Service cost	10,589				20,058
	Interest cost	8,938				12,810
	Plan participants' contributions	2,289				2,150
	Plan amendment	—				(84,004		)
	Actuarial (gains)	(38,476		)		(28,234		)
	Benefits paid	(6,021		)		(6,047		)
	Medicare Part D Subsidy received	82				442
	Benefit obligation at end of year	223,488				246,087
	Plan assets available for benefits at beginning of year	117,939				103,519
	Actual returns on plan assets	25,278				13,355
	Employer's contributions	5,029				4,962
	Plan participants' contributions	2,289				2,150
	Benefits paid	(6,021		)		(6,047		)
	Plan assets available for benefits at end of year	144,514				117,939
	Noncurrent postretirement benefit obligation	$	78,974			$	128,148
	The amounts recognized in AOCE consisted of the following components (in thousands of dollars):
		As of December 31,
		2013				2012
	Prior service credit	$	74,556			$	81,968
	Transition asset	143				286
	Unrecognized losses	(18,006		)		(78,407		)
	Deferred tax (liability)	(21,806		)		(1,618		)
	Net gains	$	34,887			$	2,229
	The components of AOCE related to the postretirement benefit costs that will be amortized into net periodic postretirement benefit costs in 2014 are estimated as follows (in thousands of dollars):
		2014
	Amortization of prior service credit	$	(7,253	)
	Amortization of transition asset	(143		)
	Amortization of unrecognized losses	1,154
	Estimated amount to be amortized from AOCE into net periodic postretirement benefit costs	$	(6,242	)
	The benefit obligation was determined by applying the terms of the plan and actuarial models. These models include various actuarial assumptions, including discount rates, assumed rates of return on plan assets, healthcare cost trend rate and cost-sharing between the Company and the retirees. The Company evaluates its actuarial assumptions on an annual basis and considers changes in these long-term factors based upon market conditions and historical experience.
	The following assumptions were used to determine net periodic benefit costs at January 1:
		For the Years Ended December 31,
		2013			2012			2011
Discount rate	4	%		4.5	%		5.6	%
Expected long-term rate of return on plan assets, net of tax	6	%		6	%		6	%
Initial healthcare cost trend rate	8	%		8.5	%		9	%
Ultimate healthcare cost trend rate	5	%		5	%		5	%
Year ultimate healthcare cost trend rate reached	2019			2019			2019
The following assumptions were used to determine benefit obligations at December 31:
	2013			2012			2011
Discount rate	4.9	%		4	%		4.5	%
Expected long-term rate of return on plan assets, net of tax	5.7	%		6	%		6	%
Initial healthcare cost trend rate	7.5	%		8	%		8.5	%
Ultimate healthcare cost trend rate	4.5	%		5	%		5	%
Year ultimate healthcare cost trend rate reached	2026			2019			2019
The discount rate assumptions reflect the rates available on high-quality fixed income debt instruments as of December 31, the measurement date, of each year.  These rates have been selected due to their similarity to the duration of the projected cash flows of the postretirement healthcare benefit plan.  As of December 31, 2013, the Company increased the discount rate from 4.0% to 4.9% to reflect the increase in the market interest rates which contributed to the decrease in the unrealized actuarial loss at December 31, 2013. The Company reviews external data and its own historical trends for healthcare costs to determine the healthcare cost trend rates. Grainger changed the duration of the healthcare trend rate to an assumed rate of increase of 7.5% declining 25 basis points a year until reaching the ultimate trend rate of 4.5% from an assumed rate of increase declining 50 basis points a year. This has the effect of moving the year that the ultimate trend rate is reached to 2026. Assumed healthcare cost trend rates have a significant effect on the amounts reported for the healthcare plans. A 1 percentage point change in assumed healthcare cost trend rates would have the following effects on 2013 results (in thousands of dollars):
	1 Percentage Point
	Increase				(Decrease)
Effect on total service and interest cost	$	2,205			$	(1,777	)
Effect on postretirement benefit obligation	29,776				(24,196		)
The Company has established a Group Benefit Trust (Trust) to fund the plan obligations and process benefit payments. All assets of the Trust are invested in equity funds designed to track to either the Standard & Poor's 500 Index (S&P 500) or the Total International Composite Index. The Total International Composite Index tracks non-U.S. stocks within developed and emerging market economies. This investment strategy reflects the long-term nature of the plan obligation and seeks to take advantage of the earnings potential of equity securities in the global markets and intends to reach a balanced allocation between U.S. and non-U.S. equities. The plan's assets are stated at fair value which represents the net asset value of shares held by the plan in the registered investment companies at the quoted market prices (Level 1 input) as of December 31 (in thousands of dollars):
	2013				2012
Registered investment companies
Fidelity Spartan U.S. Equity Index Fund	$	67,160			$	51,169
Vanguard 500 Index Fund	67,931				51,336
Vanguard Total International Stock	25,034				21,739
Total Assets	$	160,125			$	124,244
The Company uses the long-term historical return on the plan assets and the historical performance of the S&P 500 and the Total International Composite Index to develop its expected return on plan assets. In 2013, Grainger decreased the expected long-term rate of return on plan assets from 6.0% (net of tax) to 5.7% (net of tax) based on the historical average of long-term rates of return. The required use of an expected long-term rate of return on plan assets may result in recognition of income that is greater or less than the actual return on plan assets in any given year. Over time, however, the expected long-term returns are designed to approximate the actual long-term returns and, therefore, result in a pattern of income recognition that more closely matches the pattern of the services provided by the employees.
The Company's investment policies include periodic reviews by management and trustees at least annually concerning: (1) the allocation of assets among various asset classes (e.g., domestic stocks, international stocks, short-term bonds, long-term bonds, etc.); (2) the investment performance of the assets, including performance comparisons with appropriate benchmarks; (3) investment guidelines and other matters of investment policy; and (4) the hiring, dismissal or retention of investment managers.
The funding of the trust is an estimated amount that is intended to allow the maximum deductible contribution under the Internal Revenue Code of 1986 (IRC), as amended. There are no minimum funding requirements and the Company intends to follow its practice of funding the maximum deductible contribution under the IRC.
The Company forecasts the following benefit payments (which include a projection for expected future employee service) for the next ten years (in thousands of dollars):
Year		Estimated Gross Benefit Payments
2014		$	5,299
2015		6,075
2016		6,952
2017		8,001
2018		9,159
2019-2023		$	65,751

LEASES

LEASES	12 Months Ended
	Dec. 31, 2013
Notes to Financial Statements [Abstract]	'
LEASES	'
	LEASES
	The Company leases certain land, buildings and equipment under noncancellable operating leases that expire at various dates through 2036. Capital leases as of December 31, 2013 are not considered material. Many of the building leases obligate the Company to pay real estate taxes, insurance and certain maintenance costs, and contain multiple renewal provisions, exercisable at the Company's option. Leases that contain predetermined fixed escalations of the minimum rentals are recognized in rental expense on a straight-line basis over the lease term. Cash or rent abatements received upon entering into certain operating leases are also recognized on a straight-line basis over the lease term.
	At December 31, 2013, the approximate future minimum lease payments for all operating leases were as follows (in thousands of dollars):
	Year	Future Minimum Lease Payments
	2014	$	67,993
	2015	56,697
	2016	41,232
	2017	27,657
	2018	17,128
	Thereafter	19,937
	Total minimum payments required	230,644
	Less amounts representing sublease income	(4,353		)
		$	226,291
	Rent expense, including items under lease and items rented on a month-to-month basis, was $68 million for 2013 and 2012, and $72 million for 2011. These amounts are net of sublease income of $1 million for 2013 and 2012, and $2 million for 2011.

STOCK_INCENTIVE_PLANS

STOCK INCENTIVE PLANS	12 Months Ended
	Dec. 31, 2013
Notes to Financial Statements [Abstract]	'
STOCK INCENTIVE PLANS	'
	STOCK INCENTIVE PLANS
	The Company maintains stock incentive plans under which the Company may grant a variety of incentive awards to employees and directors. In 2010, the Company's shareholders approved the 2010 Incentive Plan (Plan), which replaced all prior active plans (Prior Plans). Awards previously granted under Prior Plans will remain outstanding in accordance with their terms. A total of 5.9 million shares of common stock were reserved for issuance under the Plan. As of December 31, 2013, there were 1.9 million shares available for grant under the Plan. Non-qualified stock options, performance shares, restricted stock units and deferred stock units have been granted and are outstanding under these plans.
	Pretax stock-based compensation expense was $52 million, $53 million and $51 million in 2013, 2012 and 2011, respectively. Related income tax benefits recognized in earnings were $17 million in 2013 and $18 million in 2012 and 2011.
	Options
	In 2013, 2012 and 2011, the Company issued stock option grants to employees as part of their incentive compensation. Option awards are granted with an exercise price equal to the closing market price of the Company's stock on the last trading day preceding the date of grant. The options generally vest over three years, although accelerated vesting is provided in certain circumstances. Awards generally expire 10 years from the grant date. Transactions involving stock options are summarized as follows:
		Shares Subject to Option			Weighted Average Price Per Share				Options Exercisable
	Outstanding at January 1, 2011	4,881,248			$	77.61			2,486,478
	Granted	520,327			$	149.15
	Exercised	(1,323,883	)		$	63.08
	Canceled or expired	(117,017	)		$	89.18
	Outstanding at December 31, 2011	3,960,675			$	91.53			1,808,667
	Granted	404,111			$	203.96
	Exercised	(972,015	)		$	74.14
	Canceled or expired	(34,055	)		$	105.36
	Outstanding at December 31, 2012	3,358,716			$	109.95			1,629,468
	Granted	348,054			$	245.95
	Exercised	(805,235	)		$	85.75
	Canceled or expired	(51,080	)		$	150.15
	Outstanding at December 31, 2013	2,850,455			$	132.67			1,652,417
	At December 31, 2013, there was $13 million of total unrecognized compensation expense related to nonvested option awards, which the Company expects to recognize over a weighted average period of 1.9 years.
	The following table summarizes information about stock options exercised (in thousands of dollars):
			For the years ended December 31,
			2013				2012				2011
	Fair value of options exercised		$	16,407			$	18,120			$	20,933
	Total intrinsic value of options exercised		124,752				126,138				124,441
	Fair value of options vested		20,219				15,551				13,549
	Settlements of options exercised		69,049				72,066				83,504
	Information about stock options outstanding and exercisable as of December 31, 2013, is as follows:
			Options Outstanding													Options Exercisable
						Weighted Average													Weighted Average
	Range of		Number			Remaining		Exercise				Intrinsic				Number			Remaining		Exercise		Intrinsic
	Exercise					Contractual		Price				Value							Contractual		Price		Value
	Prices					Life						(000's)							Life				(000's)
	$48.12 - $78.86		458,381			2.19 years		$	67.44			$	86,183			458,381			2.19 years		$	67.44	$	86,183
	$81.49 - $85.82		637,830			4.66 years		$	83.21			109,838				637,830			4.66 years		$	83.21	109,838
	$91.61 - $110.54		526,054			6.29 years		$	107.24			77,950				526,054			6.29 years		$	107.24	77,950
	$124.93 - $204.24		884,682			7.76 years		$	173.26			72,685				26,730			7.52 years		$	159.78	2,557
	$245.86 - $262.14		343,508			9.31 years		$	245.95			3,254				3,422			9.16 years		$	245.86	33
			2,850,455			6.09 years		$	132.67			$	349,910			1,652,417			4.55 years		$	88.06	$	276,561
	The Company uses a binomial lattice option pricing model for the valuation of stock options. The weighted average fair value of options granted in 2013, 2012 and 2011 was $51.30, $43.98 and $33.95, respectively. The fair value of each option granted in 2013, 2012 and 2011 used the following assumptions:
			For the years ended December 31,
			2013		2012		2011
	Risk-free interest rate		0.90%		1.10%		2.60%
	Expected life		6 years		6 years		6 years
	Expected volatility		25.50%		25.90%		24.60%
	Expected dividend yield		1.50%		1.60%		1.80%
	The risk-free interest rate is selected based on yields from U.S. Treasury zero-coupon issues with a remaining term approximately equal to the expected term of the options being valued. The expected life selected for options granted during each year presented represents the period of time that the options are expected to be outstanding based on historical data of option holder exercise and termination behavior. Expected volatility is based upon implied and historical volatility of the Company's closing stock price over a period equal to the expected life of each option grant. Historical Company information is also the primary basis for selection of expected dividend yield assumptions.
	Performance Shares
	The Company awards performance-based shares to certain executives. Receipt of Company stock is contingent upon the Company meeting sales growth and return on invested capital (ROIC) performance goals. Each participant is granted a base number of shares. At the end of the performance period, the number of shares granted will be increased, decreased or remain the same based upon actual Company-wide sales versus target sales. The shares, as determined at the end of the performance period, are issued at the end of the third year if the Company's average target ROIC is achieved during the vesting period.
	Performance share value is based upon closing market prices on the last trading day preceding the date of award and is charged to earnings on a ratable basis over the three-year period based on the number of shares expected to vest. Holders of performance share awards are not entitled to receive cash payments equivalent to cash dividends. If the performance shares vest, they will be settled by the Company's issuance of common stock in exchange for the performance shares on a one-for-one basis. The following table summarizes the transactions involving performance-based share awards:
		2013							2012							2011
		Shares			Weighted Average Price Per Share				Shares			Weighted Average Price Per Share				Shares			Weighted Average Price Per Share
	Beginning nonvested	117,979			$	141.86			192,740			$	109.16			177,120			$	84.74
	shares outstanding
	Issued	31,553			$	191.36			28,639			$	177.75			96,236			$	127.43
	Canceled	(7,659	)		$	148.25			(1,666	)		$	114.41			(13,056	)		$	87.24
	Vested	(84,340	)		$	130.35			(101,734	)		$	90.47			(67,560	)		$	72.86
	Ending nonvested shares	57,533			$	185.02			117,979			$	141.86			192,740			$	109.16
	outstanding
	At December 31, 2013, there was $5 million of total unrecognized compensation expense related to performance-based share awards that the Company expects to recognize over a weighted average period of 1.7 years.
	Restricted Stock Units (RSUs)
	RSUs granted vest over periods from three to seven years from issuance, although accelerated vesting is provided in certain instances. Holders of RSUs are entitled to receive cash payments equivalent to cash dividends and other distributions paid with respect to common stock. RSUs are settled by the issuance of the Company's common stock on a one-for-one basis. Compensation expense related to RSUs is based upon the closing market price on the last trading day preceding the date of award and is charged to earnings on a straight-line basis over the vesting period. The following table summarizes RSU activity:
		2013						2012						2011
	Shares		Weighted				Shares		Weighted				Shares		Weighted
			Average Price Per Share						Average Price Per Share						Average Price Per Share
Beginning nonvested units	978,888		$	118.6			1,119,488		$	100.76			1,205,787		$	88.65
Issued	139,529		$	248.28			152,995		$	204.26			242,212		$	152.55
Canceled	(54,533	)	$	141.48			(37,972	)	$	123.01			(92,202	)	$	89.57
Vested	(324,167	)	$	89.62			(255,623	)	$	88.36			(236,309	)	$	86.13
Ending nonvested units	739,717		$	154.09			978,888		$	118.6			1,119,488		$	100.76
Fair value of shares vested (in millions)	$29						$23						$20
At December 31, 2013, there was $54 million of total unrecognized compensation expense related to nonvested RSUs that the Company expects to recognize over a weighted average period of 3.3 years.
Director Stock Awards
The Company's Board of Directors receives both cash and deferred stock units (DSUs) for its services.  A DSU is the economic equivalent of a share of common stock.  The directors were each awarded $125,000 of DSUs in 2013 and $115,000 in 2012 and 2011.  The number of units granted was based on the 200-day average stock price as of January 31 of the grant year. Compensation expense related to the DSUs is based upon the closing market price on the last trading day preceeding the date of award.  DSUs vest immediately at grant and are entitled to receive dividends and other distributions with respect to common stock, which are deferred as stock units, based on the market value of the stock at relevant times. Directors can also elect to defer their cash fees in the form of DSUs. Settlement of DSUs is required to be deferred until after termination of service as a director.  The accumulated value of DSUs is recorded in Additional contributed capital as of December 31, 2013 and 2012.  During 2012, the Board approved a change in the settlement procedure to eliminate the cash settlement option. As of December 31, 2011, the outstanding DSUs were recorded as a liability in Employment-related and other noncurrent liabilities and the Company recognized expense for appreciation in value of equivalent stock units based on the market price of the Company’s common stock in 2012 and 2011. The following table summarizes DSU activity (dollars in thousands):
	2013						2012						2011
	Units		Dollars				Units		Dollars				Units		Dollars
Beginning balance	151,775		$	30,952			142,797		$	26,730			130,377		$	18,006
Dividends	2,259		559				2,273		454				2,244		350
Deferred fees	7,337		2,059				9,170		1,871				12,601		1,878
Retirement distribution	(2,503	)	(507		)		(2,465	)	(461		)		(2,425	)	(335		)
Unit appreciation	—		—				—		2,358				—		6,831
Ending balance	158,868		$	33,063			151,775		$	30,952			142,797		$	26,730

CAPITAL_STOCK

CAPITAL STOCK	12 Months Ended
	Dec. 31, 2013
Notes to Financial Statements [Abstract]	'
CAPITAL STOCK	'
	CAPITAL STOCK
	The Company had no shares of preferred stock outstanding as of December 31, 2013 and 2012. The activity related to outstanding common stock and common stock held in treasury was as follows:
		2013				2012
		Outstanding Common Stock		Treasury Stock		Outstanding Common Stock		Treasury Stock
	Balance at beginning of period	69,478,495		40,180,724		69,962,852		39,696,367
	Exercise of stock options, net of 5,134, and 5,310 shares swapped in stock-for-stock exchange, respectively	800,101		(800,101	)	966,705		(966,705	)
	Settlement of restricted stock units, net of 135,341 and 121,353 shares retained, respectively	232,483		(232,483	)	225,997		(225,997	)
	Settlement of performance share units, net of 39,874 and 23,590 shares retained, respectively	61,860		(61,860	)	44,051		(44,051	)
	Purchase of treasury shares	(1,719,001	)	1,719,001		(1,721,110	)	1,721,110
	Balance at end of period	68,853,938		40,805,281		69,478,495		40,180,724

ACCUMULATED_OTHER_COMPREHENSIV

ACCUMULATED OTHER COMPREHENSIVE EARNINGS	12 Months Ended
	Dec. 31, 2013
Notes to Financial Statements [Abstract]	'
ACCUMULATED OTHER COMPREHENSIVE EARNINGS	'
	ACCUMULATED OTHER COMPREHENSIVE EARNINGS
	The following table sets forth the components of Accumulated other comprehensive earnings (in thousands of dollars):
		As of December 31,
		2013			2012
	Foreign currency translation adjustments	$	2,900		$	85,231
	Derivative instruments	(1,944		)	(11,965		)
	Postretirement benefit plan	56,693			3,847
	Other employment-related benefit plans	(11,467		)	(9,835		)
	Deferred tax (liability) asset	(30,374		)	(11,184		)
	Total accumulated other comprehensive earnings	15,808			56,094
	Less: Foreign currency translation adjustments attributable to noncontrolling interest	(13,106		)	2,516
	Total accumulated other comprehensive earnings attributable to W.W. Grainger, Inc.	$	28,914		$	53,578
	The change in comprehensive earnings on the Postretirement benefit plan was primarily due to an increase in the discount rate. See Note 9 to the Consolidated Financial Statements.

INCOME_TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2013
Notes to Financial Statements [Abstract]	'
INCOME TAXES	'
	INCOME TAXES
	The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements or tax returns. Under this method, deferred tax assets and liabilities are determined based on the differences between the financial reporting and tax bases of assets and liabilities, using enacted tax rates in effect for the year in which the differences are expected to reverse.
	Income tax expense consisted of the following (in thousands of dollars):
		For the Years Ended December 31,
		2013			2012			2011
	Current provision:
	Federal	$	398,593		$	324,848		$	275,489
	State	42,526			40,508			49,098
	Foreign	52,277			53,564			45,405
	Total current	493,396			418,920			369,992
	Deferred tax provision (benefit)	(13,546		)	20			15,123
	Total provision	$	479,850		$	418,940		$	385,115
	Earnings before income taxes by geographical area consisted of the following (in thousands of dollars):
		For the Years Ended December 31,
		2013			2012			2011
	United States	$	1,167,558		$	982,220		$	917,820
	Foreign	120,041			135,569			133,707
		$	1,287,599		$	1,117,789		$	1,051,527
	The income tax effects of temporary differences that gave rise to the net deferred tax asset were (in thousands of dollars):
		As of December 31,
		2013			2012
	Deferred tax assets:
	Inventory	$	35,381		$	30,991
	Accrued expenses	38,368			26,706
	Accrued employment-related benefits	123,555			139,931
	Foreign operating loss carryforwards	70,204			67,148
	Other	30,862			31,008
	Deferred tax assets	298,370			295,784
	Less valuation allowance	(62,825		)	(54,434		)
	Deferred tax assets, net of valuation allowance	$	235,545		$	241,350
	Deferred tax liabilities:
	Property, buildings and equipment	(38,210		)	(37,876		)
	Intangibles	(119,923		)	(114,955		)
	Software	(17,492		)	(16,653		)
	Prepaids	(18,945		)	(20,509		)
	Other	(17,378		)	(19,291		)
	Deferred tax liabilities	(211,948		)	(209,284		)
	Net deferred tax asset	$	23,597		$	32,066
	The net deferred tax asset is classified as follows:
	Current assets	$	75,819		$	55,967
	Noncurrent assets	16,209			51,536
	Noncurrent liabilities (foreign)	(68,431		)	(75,437		)
	Net deferred tax asset	$	23,597		$	32,066
	At December 31, 2013, the Company had $262 million of operating loss carryforwards related primarily to foreign operations. Some of the operating loss carryforwards may expire at various dates through 2023. The Company has recorded a valuation allowance, which represents a provision for uncertainty as to the realization of the tax benefits of these carryforwards. In addition, the Company recorded a valuation allowance to reflect the estimated amount of deferred tax assets that may not be realized.
	The changes in the valuation allowance were as follows (in thousands of dollars):
		For the Years Ended December 31,
		2013			2012
	Beginning balance	$	54,434		$	53,739
	Increase related to foreign net operating loss carryforwards	8,391			695
	Ending balance	$	62,825		$	54,434
	A reconciliation of income tax expense with federal income taxes at the statutory rate follows (in thousands of dollars):
		For the Years Ended December 31,
		2013			2012			2011
	Federal income tax at the 35% statutory rate	$	450,660		$	391,226		$	368,034
	State income taxes, net of federal income tax benefit	27,430			26,099			32,226
	Other - net	1,760			1,615			(15,145		)
	Income tax expense	$	479,850		$	418,940		$	385,115
	Effective tax rate	37.3		%	37.5		%	36.6		%
	In 2011, other - net included the tax benefit related to settlement of various tax reviews during 2011 and the benefit of tax law changes in Japan enacted in the fourth quarter of 2011.
	Undistributed earnings of foreign subsidiaries at December 31, 2013, amounted to $386 million. No provision for deferred U.S. income taxes has been made for these subsidiaries because the Company intends to permanently reinvest such earnings in its foreign operations. If at some future date these earnings cease to be permanently invested, the Company may be subject to U.S. income taxes, foreign withholding, and other taxes on such amounts, which cannot be reasonably estimated at this time.
	The changes in the liability for tax uncertainties, excluding interest, are as follows (in thousands of dollars):
		2013			2012
	Balance at beginning of year	$	40,937		$	22,760
Additions to tax positions related to the current year	8,396			11,369
Additions for tax positions of prior years	2,308			8,977
Reductions for tax positions of prior years	(7,242		)	(1,447		)
Reductions due to statute lapse	(18		)	(737		)
Settlements, audit payments, refunds - net	(4,064		)	15
Balance at end of year	$	40,317		$	40,937
The Company classifies the liability for tax uncertainties in Deferred income taxes and tax uncertainties. Included in this amount are $8 million and $6 million at December 31, 2013 and 2012, respectively, of tax positions for which the ultimate deductibility is highly certain but for which there is uncertainty about the timing of such deductibility. Any changes in the timing of deductibility of these items would not affect the annual effective tax rate but would accelerate the payment of cash to the taxing authorities to an earlier period. The reduction to tax positions of prior years in 2013 related primarily to law changes, conclusion of audits and audit settlements.
The Company regularly undergoes examination of its federal income tax returns by the Internal Revenue Service (IRS). The Company's federal tax returns for 2009 and 2010 are currently under audit by the IRS, and the tax years 2011 through 2013 are open. The Company is also subject to audit by state, local and foreign taxing authorities.  Tax years 2002 - 2013 remain subject to state and local audits and 2006 - 2013 remain subject to foreign audits.  The estimated amount of liability associated with the Company's uncertain tax positions may change within the next 12 months due to the pending audit activity, expiring statutes or tax payments. A reasonable estimate of such change cannot be made.
The Company recognizes interest expense in the provision for income taxes. During 2013 and 2012, the Company recognized an expense of $2 million and $1 million, respectively. During 2011, the Company recognized a net benefit of $1 million, primarily due to settlement of audits and a statute lapse. As of December 31, 2013 and 2012, the Company accrued approximately $4 million and $2 million, respectively, for interest.

EARNINGS_PER_SHARE

EARNINGS PER SHARE	12 Months Ended
	Dec. 31, 2013
Notes to Financial Statements [Abstract]	'
EARNINGS PER SHARE	'
	EARNINGS PER SHARE
	The Company’s unvested Restricted Stock Units and Directors' Deferred Stock Units that contain nonforfeitable rights to dividends meet the criteria of a participating security. Under the two-class method, earnings are allocated between common stock and participating securities. The presentation of basic and diluted earnings per share is required only for each class of common stock and not for participating securities. As such, the Company presents basic and diluted earnings per share for its one class of common stock.
	The two-class method includes an earnings allocation formula that determines earnings per share for each class of common stock according to dividends declared and undistributed earnings for the period. The Company’s reported net earnings is reduced by the amount allocated to participating securities to arrive at the earnings allocated to common stock shareholders for purposes of calculating earnings per share.
	The dilutive effect of participating securities is calculated using the more dilutive of the treasury stock or the two-class method. The Company has determined the two-class method to be the more dilutive. As such, the earnings allocated to common stock shareholders in the basic earnings per share calculation is adjusted for the reallocation of undistributed earnings to participating securities to arrive at the earnings allocated to common stock shareholders for calculating the diluted earnings per share.
	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):
		For the Years Ended December 31,
		2013			2012			2011
	Net earnings attributable to W.W. Grainger, Inc. as reported	$	797,036		$	689,881		$	658,423
	Distributed earnings available to participating securities	(3,304		)	(3,641		)	(3,216		)
	Undistributed earnings available to participating securities	(8,348		)	(8,704		)	(9,635		)
	Numerator for basic earnings per share - Undistributed and distributed earnings available to common shareholders	785,384			677,536			645,572
	Undistributed earnings allocated to participating securities	8,348			8,704			9,635
	Undistributed earnings reallocated to participating securities	(8,218		)	(8,540		)	(9,438		)
	Numerator for diluted earnings per share - Undistributed and distributed earnings available to common shareholders	$	785,514		$	677,700		$	645,769
	Denominator for basic earnings per share – weighted average shares	69,455,507			69,811,881			69,690,854
	Effect of dilutive securities	1,120,925			1,369,852			1,485,304
	Denominator for diluted earnings per share – weighted average shares adjusted for dilutive securities	70,576,432			71,181,733			71,176,158
	Earnings per share two-class method
	Basic	$	11.31		$	9.71		$	9.26
	Diluted	$	11.13		$	9.52		$	9.07

SEGMENT_INFORMATION

SEGMENT INFORMATION	12 Months Ended
	Dec. 31, 2013
Notes to Financial Statements [Abstract]	'
SEGMENT INFORMATION	'
	SEGMENT INFORMATION
	The Company has two reportable segments:  the United States and Canada.  The United States operating segment reflects the results of the Company’s U.S. business.  The Canada operating segment reflects the results for Acklands – Grainger Inc., the Company’s Canadian business.  Other businesses include the Company's operations in Europe, Asia, Latin America and other U.S. operations. These businesses individually do not meet the criteria of a reportable segment. Operating segments generate revenue almost exclusively through the distribution of maintenance, repair and operating supplies, as service revenues account for less than 1% of total revenues for each operating segment.
	The accounting policies of the segments are the same as those described in the summary of significant accounting policies. Intersegment transfer prices are established at external selling prices, less costs not incurred due to a related party sale. The segment results include certain centrally incurred costs for shared services that are charged to the segments based upon the relative level of service used by each operating segment.
	Following is a summary of segment results (in thousands of dollars):
		2013
		United States			Canada			Other Businesses			Total
	Total net sales	$	7,413,712		$	1,114,285		$	1,040,473		$	9,568,470
	Intersegment net sales	(128,660		)	(300		)	(1,752		)	(130,712		)
	Net sales to external customers	7,285,052			1,113,985			1,038,721			9,437,758
	Segment operating earnings	1,304,175			128,768			7,599			1,440,542
	Segment assets	2,045,564			392,147			359,007			2,796,718
	Depreciation and amortization	116,392			14,309			19,754			150,455
	Additions to long-lived assets	$	177,046		$	63,821		$	23,951		$	264,818
		2012
		United States			Canada			Other Businesses			Total
	Total net sales	$	6,925,842		$	1,105,782		$	1,006,762		$	9,038,386
	Intersegment net sales	(87,249		)	(363		)	(729		)	(88,341		)
	Net sales to external customers	6,838,593			1,105,419			1,006,033			8,950,045
	Segment operating earnings	1,132,722			127,412			20,289			1,280,423
	Segment assets	1,884,102			387,915			347,905			2,619,922
	Depreciation and amortization	99,229			14,058			19,202			132,489
	Additions to long-lived assets	$	182,985		$	46,330		$	21,611		$	250,926
		2011
		United States			Canada			Other Businesses			Total
	Total net sales	$	6,501,343		$	992,823		$	647,666		$	8,141,832
	Intersegment net sales	(62,766		)	(163		)	(718		)	(63,647		)
	Net sales to external customers	6,438,577			992,660			646,948			8,078,185
	Segment operating earnings	1,066,324			107,582			30,984			1,204,890
	Segment assets	1,845,703			335,900			331,896			2,513,499
	Depreciation and amortization	100,017			12,840			11,035			123,892
	Additions to long-lived assets	$	148,803		$	29,744		$	13,402		$	191,949
	Following are reconciliations of the segment information with the consolidated totals per the financial statements (in thousands of dollars):
		2013			2012			2011
	Operating earnings:
	Total operating earnings for reportable segments	$	1,440,542		$	1,280,423		$	1,204,890
	Unallocated expenses	(143,688		)	(149,298		)	(152,461		)
	Total consolidated operating earnings	$	1,296,854		$	1,131,125		$	1,052,429
	Assets:
	Assets for reportable segments	$	2,796,718		$	2,619,922		$	2,513,499
	Other current and noncurrent assets	2,118,298			1,967,480			1,749,029
	Unallocated assets	351,312			427,196			453,534
	Total consolidated assets	$	5,266,328		$	5,014,598		$	4,716,062
		2013
		Segment			Unallocated			Consolidated Total
		Totals
	Other significant items:
	Depreciation and amortization	$	150,455		$	14,447		$	164,902
	Additions to long-lived assets	$	264,818		$	12,782		$	277,600
					Revenues			Long-lived Assets
	Geographic information:
	United States				$	7,290,746		$	1,004,806
	Canada				1,126,559			176,491
	Other foreign countries				1,020,453			134,535
					$	9,437,758		$	1,315,832
		2012
		Segment			Unallocated			Consolidated Total
		Totals
	Other significant items:
	Depreciation and amortization	$	132,489		$	13,123		$	145,612
	Additions to long-lived assets	$	250,926		$	6,998		$	257,924
					Revenues			Long-lived Assets
	Geographic information:
	United States				$	6,786,361		$	944,400
Canada				1,120,470			136,644
Other foreign countries				1,043,214			135,438
				$	8,950,045		$	1,216,482
	2011
	Segment			Unallocated			Consolidated Total
	Totals
Other significant items:
Depreciation and amortization	$	123,892		$	13,319		$	137,211
Additions to long-lived assets	$	191,949		$	5,665		$	197,614
				Revenues			Long-lived Assets
Geographic information:
United States				$	6,388,506		$	872,947
Canada				998,014			102,085
Other foreign countries				691,665			129,014
				$	8,078,185		$	1,104,046
Revenues are attributed to countries based on the ship-to location of the customer.
Unallocated expenses and unallocated assets primarily relate to the Company headquarters' support services, which are not part of any business segment, as well as intercompany eliminations. Unallocated expenses include payroll and benefits, depreciation and other costs associated with headquarters-related support services. Unallocated assets include non-operating cash and cash equivalents, certain prepaid expenses and property, buildings and equipment-net.
Assets for reportable segments include net accounts receivable and first-in, first-out inventory which are reported to the Company's Chief Operating Decision Maker. Long-lived assets consist of property, buildings, equipment and capitalized software.
Depreciation and amortization presented above includes depreciation of long-lived assets and amortization of capitalized software.

SELECTED_QUARTERLY_FINANCIAL_D

SELECTED QUARTERLY FINANCIAL DATA	12 Months Ended
	Dec. 31, 2013
Notes to Financial Statements [Abstract]	'
SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED)	'
	SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED)
	A summary of selected quarterly information for 2013 and 2012 is as follows (in thousands of dollars, except for per share amounts):
			2013 Quarter Ended
			31-Mar		30-Jun		30-Sep		31-Dec		Total
	Net sales		$	2,280,435	$	2,381,561	$	2,398,530	$	2,377,232	$	9,437,758
	Cost of merchandise sold		1,248,699		1,334,577		1,347,164		1,370,835		5,301,275
	Gross profit		1,031,736		1,046,984		1,051,366		1,006,397		4,136,483
	Warehousing, marketing and		688,431		696,912		704,651		749,635		2,839,629
	administrative expenses
	Operating earnings		343,305		350,072		346,715		256,762		1,296,854
	Net earnings attributable to W.W. Grainger, Inc.		211,838		217,660		210,789		156,749		797,036
	Earnings per share - basic		2.99		3.08		2.99		2.24		11.31
	Earnings per share - diluted		$	2.94	$	3.03	$	2.95	$	2.2	$	11.13
			2012 Quarter Ended
			31-Mar		30-Jun		30-Sep		31-Dec		Total
	Net sales		$	2,193,445	$	2,249,275	$	2,281,205	$	2,226,120	$	8,950,045
	Cost of merchandise sold		1,219,113		1,270,932		1,287,245		1,256,595		5,033,885
	Gross profit		974,332		978,343		993,960		969,525		3,916,160
	Warehousing, marketing and		669,971		664,343		739,634		711,087		2,785,035
	administrative expenses
	Operating earnings		304,361		314,000		254,326		258,438		1,131,125
	Net earnings attributable to W.W. Grainger, Inc.		187,516		190,704		155,394		156,267		689,881
	Earnings per share - basic		2.63		2.68		2.19		2.21		9.71
	Earnings per share - diluted (1)		$	2.57	$	2.63	$	2.15	$	2.17	$	9.52
	-1	The third quarter of 2012 included a $0.66 per share expense related to the settlement of disputes involving the GSA and USPS contracts.

CONTINGENCIES_AND_LEGAL_MATTER

CONTINGENCIES AND LEGAL MATTERS	12 Months Ended
	Dec. 31, 2013
Notes to Financial Statements [Abstract]	'
CONTINGENCIES AND LEGAL MATTERS	'
	CONTINGENCIES AND LEGAL MATTERS
	The Company has been named, along with numerous other nonaffiliated companies, as a defendant in litigation in various states involving asbestos and/or silica. These lawsuits typically assert claims of personal injury arising from alleged exposure to asbestos and/or silica as a consequence of products purportedly distributed by the Company. In 2013, the Company was named in lawsuits relating to asbestos involving approximately 70 new plaintiffs, and lawsuits relating to asbestos and/or silica involving approximately 67 plaintiffs were dismissed with respect to the Company, typically based on the lack of product identification.
	As of January 23, 2014, the Company is named in cases filed on behalf of approximately 1,929 plaintiffs in which there is an allegation of exposure to asbestos and/or silica. The Company has denied, or intends to deny, the allegations in all of the above-described lawsuits.  If a specific product distributed by the Company is identified in any of these lawsuits, the Company would attempt to exercise indemnification remedies against the product manufacturer.  In addition, the Company believes that a substantial number of these claims are covered by insurance.  The Company has entered into agreements with its major insurance carriers relating to the scope, coverage and costs of defense of lawsuits involving claims of exposure to asbestos.  While the Company is unable to predict the outcome of these lawsuits, it believes that the ultimate resolution will not have, either individually or in the aggregate, a material adverse effect on the Company's consolidated financial position or results of operations.
	As previously disclosed, on December 26, 2012, the Company announced that it entered into a definitive settlement agreement (the “Agreement”) with the United States of America, acting through the Civil Division of the United States Department of Justice (DOJ) of certain claims related to its contracts with the General Services Administration (GSA) and the United States Postal Service. The Agreement did not contain any admission of wrongdoing by the Company. The amounts due under the Agreement have been fully paid. The Company continues to maintain a $6 million reserve for liabilities associated with alleged claims for tax, freight and billing errors related to its GSA contract that were not covered by the Agreement and which remain unresolved.
	From time to time the Company is involved in various other legal and administrative proceedings that are incidental to its business, including claims related to product liability, general negligence, contract disputes, environmental issues, wage and hour laws, intellectual property, employment practices, regulatory compliance or other matters and actions brought by employees, consumers, competitors, suppliers or governmental entities. As a government contractor selling to federal, state and local governmental entities, the Company is also subject to governmental or regulatory inquiries or audits or other proceedings, including those related to pricing compliance. It is not expected that the ultimate resolution of any of these matters will have, either individually or in the aggregate, a material adverse effect on the Company's consolidated financial position or results of operations.

SUMMARY_OF_SIGNIFICANT_ACCOUNT1

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2013
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]	'
PRINCIPLES OF CONSOLIDATION	'
	PRINCIPLES OF CONSOLIDATION
	The consolidated financial statements include the accounts of the Company and its subsidiaries. All significant intercompany transactions are eliminated from the consolidated financial statements.
EQUITY METHOD OF ACCOUNTING FOR INVESTMENTS	'
	EQUITY METHOD OF ACCOUNTING FOR INVESTMENTS
	For investments in which the Company owns or controls from 20% to 50% of the voting shares, the equity method of accounting is used. The Company also accounts for investments below 20% using the equity method when significant influence can be exercised over the operating and financial policies of the investee company.
	In October 2011, the Company divested its 49% stake in a joint venture, MRO Korea Co., Ltd., for $12 million, resulting in a pretax gain of $8 million ($5 million after-tax) net of the cumulative foreign currency losses reclassified from Accumulated other comprehensive earnings. The Company previously accounted for this investment under the equity method.
USE OF ESTIMATES	'
	USE OF ESTIMATES
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, revenues and expenses, and the disclosure of contingent liabilities. Actual results could differ from those estimates.
FOREIGN CURRENCY TRANSLATION	'
	FOREIGN CURRENCY TRANSLATION
	The financial statements of the Company's foreign subsidiaries are measured using the local currency as the functional currency. Net exchange gains or losses resulting from the translation of financial statements of foreign operations and related long-term debt and derivative instruments are recorded as a separate component of other comprehensive earnings. See Note 13 to the Consolidated Financial Statements.
RECLASSIFICATIONS	'
	RECLASSIFICATIONS
	Certain amounts in the 2012 and 2011 financial statements, as previously reported, have been reclassified to conform to the 2013 presentation.
REVENUE RECOGNITION	'
	REVENUE RECOGNITION
	Revenues recognized include product sales, billings for freight and handling charges and fees earned for services provided. The Company recognizes product sales and billings for freight and handling charges primarily on the date products are shipped to, or picked up by, the customer. In cases where the product is shipped directly to the customer, the company recognizes revenue at the time of shipment on a gross basis. The Company's standard shipping terms are FOB shipping point. On occasion, the Company will negotiate FOB destination terms. These sales are recognized upon delivery to the customer. eCommerce revenues, which accounted for 33% of total 2013 revenues, are recognized on the same terms as revenues through other channels. Fee revenues, which accounted for less than 1% of total 2013 revenues, are recognized after services are completed. Taxes collected from customers and remitted to governmental authorities are presented on a net basis and are not included in revenue.
COST OF MERCHANDISE SOLD	'
	COST OF MERCHANDISE SOLD
	Cost of merchandise sold includes product and product-related costs, vendor consideration, freight-out and handling costs. The Company defines handling costs as those costs incurred to fulfill a shipped sales order.
VENDOR CONSIDERATION	'
	VENDOR CONSIDERATION
	The Company receives rebates and allowances from its vendors to promote their products. The Company utilizes numerous advertising programs to promote its vendors' products, including catalogs and other printed media, Internet, radio and other marketing programs. Most of these programs relate to multiple vendors, which makes supporting the specific, identifiable and incremental criteria difficult, and would require numerous assumptions and judgments. Based on the inexact nature of trying to track reimbursements to the advertising expenditure for each vendor, the Company treats most vendor advertising allowances as a reduction to Cost of merchandise sold rather than a reduction of operating (advertising) expenses. Rebates earned from vendors that are based on product purchases are capitalized into inventory as part of product purchase price. These rebates are credited to Cost of merchandise sold based on sales. Vendor rebates that are earned based on products sold are credited directly to Cost of merchandise sold.
ADVERTISING	'
	ADVERTISING
	Advertising costs are expensed in the year the related advertisement is first presented. Advertising expense was $178 million, $173 million and $145 million for 2013, 2012 and 2011, respectively. Most vendor-provided allowances are classified as an offset to Cost of merchandise sold. For additional information see VENDOR CONSIDERATION above.
	Catalog expense is amortized equally over the life of the catalog, beginning in the month of its distribution. Advertising costs for catalogs that have not been distributed by year-end are capitalized as Prepaid expenses. Amounts included in Prepaid expenses at December 31, 2013 and 2012, were $36 million and $46 million, respectively.
WAREHOUSING, MARKETING AND ADMINISTRATIVE EXPENSES	'
	WAREHOUSING, MARKETING AND ADMINISTRATIVE EXPENSES
	Included in this category are purchasing, branch operations, information services, and marketing and selling expenses, as well as other types of general and administrative costs.
STOCK INCENTIVE PLANS	'
	STOCK INCENTIVE PLANS
	The Company measures all share-based payments using fair-value-based methods and records compensation expense related to these payments over the vesting period. See Note 11 to the Consolidated Financial Statements.
INCOME TAXES	'
	INCOME TAXES
	Income taxes are recognized during the year in which transactions enter into the determination of financial statement income, with deferred taxes being provided for temporary differences between financial and tax reporting. The Company recognizes in the financial statements a provision for tax uncertainties, resulting from application of complex tax regulations in multiple tax jurisdictions. See Note 14 to the Consolidated Financial Statements.
OTHER COMPREHENSIVE EARNINGS (LOSSES)	'
	OTHER COMPREHENSIVE EARNINGS (LOSSES)
	The Company's Other comprehensive earnings (losses) include foreign currency translation adjustments, changes in fair value of derivatives designated as hedges and unrecognized gains (losses) on postretirement and other employment-related benefit plans. See Note 13 to the Consolidated Financial Statements.
CASH AND CASH EQUIVALENTS	'
	CASH AND CASH EQUIVALENTS
	The Company considers investments in highly liquid debt instruments, purchased with an original maturity of 90 days or less, to be cash equivalents.
CONCENTRATION OF CREDIT RISK	'
	CONCENTRATION OF CREDIT RISK
	The Company places temporary cash investments with institutions of high credit quality and, by policy, limits the amount of credit exposure to any one institution.
	The Company has a broad customer base representing many diverse industries doing business in all regions of the United States, Canada, Europe, Asia and Latin America. Consequently, no significant concentration of credit risk is considered to exist.
ALLOWANCE FOR DOUBTFUL ACCOUNTS	'
	ALLOWANCE FOR DOUBTFUL ACCOUNTS
	The Company establishes reserves for customer accounts that are potentially uncollectible. The method used to estimate the allowances is based on several factors, including the age of the receivables and the historical ratio of actual write-offs to the age of the receivables. These analyses also take into consideration economic conditions that may have an impact on a specific industry, group of customers or a specific customer.
INVENTORIES	'
	INVENTORIES
	Inventories are valued at the lower of cost or market. Cost is determined primarily by the last-in, first-out (LIFO) method, which accounts for approximately 59% of total inventory. For the remaining inventory, cost is determined by the first-in, first-out (FIFO) method.
PROPERTY, BUILDINGS AND EQUIPMENT	'
	PROPERTY, BUILDINGS AND EQUIPMENT
	Property, buildings and equipment are valued at cost. For financial statement purposes, depreciation and amortization are provided in amounts sufficient to relate the cost of depreciable assets to operations over their estimated service lives, principally on the declining-balance and sum-of-the-years-digits depreciation methods. The Company's international businesses record depreciation expense primarily on a straight-line basis. The principal estimated useful lives for determining depreciation are as follows:
	Buildings, structures and improvements	10 to 30 years
	Furniture, fixtures, machinery and equipment	3 to 10 years
	Improvements to leased property are amortized over the initial terms of the respective leases or the estimated service lives of the improvements, whichever is shorter.
	The Company capitalized interest costs of $1 million in each of years 2013, 2012 and 2011.
LONG-LIVED ASSETS	'
	LONG-LIVED ASSETS
	The carrying value of long-lived assets is evaluated whenever events or changes in circumstances indicate that the carrying value of the asset may be impaired. An impairment loss is recognized when estimated undiscounted future cash flows resulting from use of the asset, including disposition, are less than the carrying value of the asset. Impairment is measured as the amount by which the carrying amount exceeds the fair value.
	The Company recognized impairment charges of $0.4 million, $2 million and $8 million in 2013, 2012 and 2011, respectively, included in Warehousing, marketing and administrative expenses, to reduce the carrying value of certain long-lived assets to their estimated fair value pursuant to impairment indicators for property currently held for sale, lease terminations, idle assets and branch closures.
CAPITALIZED SOFTWARE	'
	CAPITALIZED SOFTWARE
	The Company capitalizes certain costs related to the purchase and development of internal-use software. Amortization of capitalized software is on a straight-line basis over three and five years. Amortization begins when the software is available for its intended use. Amortization expense was $23 million, $16 million and $19 million for the years ended December 31, 2013, 2012 and 2011, respectively. Capitalized software was $107 million and $72 million at December 31, 2013 and 2012, respectively and are included in Other assets and intangibles - net on the Consolidated Balance Sheets.
GOODWILL AND OTHER INTANGIBLES	'
	GOODWILL AND OTHER INTANGIBLES
	Goodwill is recognized as the excess cost of an acquired entity over the net amount assigned to assets acquired and liabilities assumed. Goodwill is not amortized, but rather tested for impairment on an annual basis and more often if circumstances require. Impairment losses are recognized whenever the implied fair value of goodwill is less than its carrying value.
	The Company recognizes an acquired intangible apart from goodwill whenever the intangible arises from contractual or other legal rights, or whenever it can be separated or divided from the acquired entity and sold, transferred, licensed, rented or exchanged, either individually or in combination with a related contract, asset or liability. Such intangibles are amortized over their estimated useful lives unless the estimated useful life is determined to be indefinite. Amortizable intangible assets are being amortized primarily over useful lives of three to 22 years. The straight-line method of amortization is used as it has been determined to approximate customer attrition patterns and the use pattern of the assets. Impairment losses are recognized if the carrying amount of an intangible, subject to amortization, is not recoverable from expected future cash flows and its carrying amount exceeds its fair value.
	The Company also maintains intangible assets with indefinite lives, which are not amortized. These intangibles are tested for impairment on an annual basis and more often if circumstances require. Impairment losses are recognized whenever the implied fair value of these assets is less than their carrying value. See Note 2 and Note 3 to the Consolidated Financial Statements.
FAIR VALUE OF FINANCIAL INSTRUMENTS	'
	FAIR VALUE OF FINANCIAL INSTRUMENTS
	The carrying amounts of cash and cash equivalents, receivables, and accounts payable approximate fair value due to the short-term nature of these financial instruments. The carrying value of long-term debt also approximates fair value due to the variable interest rates. The fair value of the Company's qualifying derivative instruments is recorded in the Consolidated Balance Sheets and is discussed in more detail in Note 8 to the Consolidated Financial Statements.
DERIVATIVE INSTRUMENTS AND HEDGING	'
	DERIVATIVE INSTRUMENTS AND HEDGING
	The Company uses derivative financial instruments to manage exposures to fluctuations in interest rates and foreign currency exchange rates. The Company does not enter into derivative financial instruments for trading or speculative purposes. All derivative instruments are recognized as either assets or liabilities in the balance sheet at their fair value. Changes in the fair value of derivatives are recognized in net earnings or other comprehensive earnings (losses) depending on whether the derivative is designated as part of a qualifying hedging relationship. The ineffective portion of a qualifying hedging derivative and derivatives not designated as a hedge are recognized immediately in earnings. Instruments that do not qualify for hedge accounting are marked to market with the change recognized in current period earnings. See Note 8 and Note 13 to the Consolidated Financial Statements for additional information on the Company's derivative activities.
INSURANCE RESERVES	'
	INSURANCE RESERVES
	The Company purchases insurance for catastrophic exposures and those risks required to be insured by law. It also retains a significant portion of the risk of certain losses related to workers' compensation, general liability and property losses through the utilization of high deductibles and self-insured retentions. Reserves for these potential losses are based on an external analysis of the Company's historical claims results and other actuarial assumptions.
WARRANTY RESERVES	'
	WARRANTY RESERVES
	The Company generally warrants the products it sells against defects for one year. For a significant portion of warranty claims, the manufacturer of the product is responsible for expenses. For warranty expenses not covered by the manufacturer, the Company provides a reserve for future costs based primarily on historical experience. Warranty reserves were $4 million at December 31, 2013 and 2012
NEW ACCOUNTING STANDARDS	'
	NEW ACCOUNTING STANDARDS
	In February 2013, the Financial Accounting Standards Board issued Accounting Standards Update (ASU) 2013-02, Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income. Under ASU 2013-02, an entity is required to provide information about the amounts reclassified out of accumulated other comprehensive income (AOCI) by component. In addition, an entity is required to present, either on the face of the financial statements or in the notes, significant amounts reclassified out of AOCI by the respective line items of net income, but only if the amount reclassified is required to be reclassified in its entirety in the same reporting period. For amounts that are not required to be reclassified in their entirety to net income, an entity is required to cross-reference to other disclosures that provide details about those amounts. ASU 2013-02 does not change the current requirements for reporting net income or other comprehensive income in the financial statements. ASU 2013-02 is effective for interim and annual periods beginning after December 15, 2012 and early adoption is permitted. The Company adopted ASU 2013-02 in the first quarter of 2013. The adoption of ASU 2013-02 did not have a material impact on the consolidated financial statements.
	In July 2013, the Financial Accounting Standards Board issued ASU 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. The guidance requires the presentation of certain unrecognized tax benefits as reductions to deferred tax assets rather than as liabilities in the condensed consolidated balance sheets when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. The amendments will be effective for interim and annual periods beginning after December 15, 2013. Early adoption and retrospective application are permitted. The Company does not expect the adoption of ASU 2013-11 to have a material impact on the Company’s consolidated financial statements.

GOODWILL_AND_OTHER_INTANGIBLE_1

GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)	12 Months Ended
	Dec. 31, 2013
GOODWILL AND OTHER INTANGIBLES [Abstract]	'
Schedule of Goodwill	'
	The changes in the carrying amount of goodwill by segment are as follows (in thousands of dollars):
			United States				Canada				Other Businesses				Total
	Balance at January 1, 2012		$	151,231			$	150,645			$	207,307			$	509,183
	Acquisitions		23,385				—				12,466				35,851
	Purchase price adjustments		—				—				4,523				4,523
	Impairment		(4,177		)		—				—				(4,177		)
	Translation		—				4,130				(5,840		)		(1,710		)
	Balance at December 31, 2012		170,439				154,775				218,456				543,670
	Acquisitions		35,820				—				—				35,820
	Purchase price adjustments		(12,900		)		—				2,067				(10,833		)
	Impairment		(12,861		)		—				(11,260		)		(24,121		)
	Translation		—				(10,187		)		(8,882		)		(19,069		)
	Balance at December 31, 2013		$	180,498			$	144,588			$	200,381			$	525,467
Schedule of Finite-Lived Intangible Assets by Major Class	'
	Intangible assets included in Other assets and intangibles - net in the Consolidated Balance Sheets were comprised of the following (in thousands of dollars):
		As of December 31,
		2013												2012
		Gross carrying amount				Accumulated amortization				Net carrying amount				Gross carrying amount				Accumulated amortization		Net carrying amount
	Amortized customer lists and relationships	$	350,760			$	134,889			$	215,871			$	279,068			$	124,137	$	154,931
	Amortized trademarks, trade names and other	38,670				23,919				14,751				34,907				21,885		13,022
	Non-amortized trade names	72,790				—				72,790				74,782				—		74,782
	Total intangible assets	$	462,220			$	158,808			$	303,412			$	388,757			$	146,022	$	242,735
Schedule of Expected Amortization Expense	'
	Estimated amortization expense for future periods is as follows (in thousands of dollars):
	Year		Expense
	2014		$	20,257
	2015		20,057
	2016		18,587
	2017		17,630
	2018		16,580
	Thereafter		137,511

ALLOWANCE_FOR_DOUBTFUL_ACCOUNT1

ALLOWANCE FOR DOUBTFUL ACCOUNTS (Tables)	12 Months Ended
	Dec. 31, 2013
NOTE 4 - ALLOWANCE FOR DOUBTFUL ACCOUNTS [Abstract]	'
Schedule of Allowance for Doubtful Accounts	'
	The following table shows the activity in the allowance for doubtful accounts (in thousands of dollars):
		For the Years Ended December 31,
		2013			2012
	Balance at beginning of period	$	19,449		$	18,801
	Provision for uncollectible accounts	8,855			9,504
	Write-off of uncollectible accounts, net of recoveries	(7,942		)	(9,100		)
	Business acquisitions, foreign currency and other	(266		)	244
	Balance at end of period	$	20,096		$	19,449

LONGTERM_DEBT_Tables

LONG-TERM DEBT (Tables)	12 Months Ended
	Dec. 31, 2013
Long-term Debt, Unclassified [Abstract]	'
Schedule of Long-term Debt Instruments	'
	Long-term debt consisted of the following (in thousands of dollars):
		As of December 31,
		2013			2012
	Bank term loan	$	292,500		$	300,000
	Euro-denominated bank term loan	158,067			158,328
	Other	25,375			27,245
	Less current maturities	(30,429		)	(18,525		)
		$	445,513		$	467,048
Schedule of Maturities of Long-term Debt	'
	The scheduled aggregate principal payments related to long-term debt are due as follows (in thousands of dollars):
	Year		Payment Amount
	2014		$	30,429
	2015		35,124
	2016		393,886
	2017		1,392
	2018		1,106
	Thereafter		14,005

EMPLOYEE_BENEFITS_Tables

EMPLOYEE BENEFITS (Tables)	12 Months Ended
	Dec. 31, 2013
Notes to Financial Statements [Abstract]	'
Schedule of Net Benefit Costs	'
	The net periodic benefits costs charged to operating expenses, which were valued with a measurement date of January 1 for each year, consisted of the following components (in thousands of dollars):
		For the Years Ended December 31,
		2013				2012				2011
	Service cost	$	10,589			$	20,058			$	15,762
	Interest cost	8,938				12,810				13,352
	Expected return on assets	(7,076		)		(6,210		)		(5,790		)
	Amortization of prior service credit	(7,412		)		(495		)		(495		)
	Amortization of transition asset	(143		)		(143		)		(143		)
	Amortization of unrecognized losses	3,724				4,827				3,269
	Net periodic benefits costs	$	8,620			$	30,847			$	25,955
Schedule of Accumulated and Projected Benefit Obligations	'
	Reconciliations of the beginning and ending balances of the postretirement benefit obligation, which is calculated using a December 31 measurement date, the fair value of plan assets and the funded status of the benefit obligation follow (in thousands of dollars):
		2013				2012
	Benefit obligation at beginning of year	$	246,087			$	328,912
	Service cost	10,589				20,058
	Interest cost	8,938				12,810
	Plan participants' contributions	2,289				2,150
	Plan amendment	—				(84,004		)
	Actuarial (gains)	(38,476		)		(28,234		)
	Benefits paid	(6,021		)		(6,047		)
	Medicare Part D Subsidy received	82				442
	Benefit obligation at end of year	223,488				246,087
	Plan assets available for benefits at beginning of year	117,939				103,519
	Actual returns on plan assets	25,278				13,355
	Employer's contributions	5,029				4,962
	Plan participants' contributions	2,289				2,150
	Benefits paid	(6,021		)		(6,047		)
	Plan assets available for benefits at end of year	144,514				117,939
	Noncurrent postretirement benefit obligation	$	78,974			$	128,148
Schedule of Amounts Recognized in Other Comprehensive Income (Loss)	'
	The amounts recognized in AOCE consisted of the following components (in thousands of dollars):
		As of December 31,
		2013				2012
	Prior service credit	$	74,556			$	81,968
	Transition asset	143				286
	Unrecognized losses	(18,006		)		(78,407		)
	Deferred tax (liability)	(21,806		)		(1,618		)
	Net gains	$	34,887			$	2,229
Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year	'
	The components of AOCE related to the postretirement benefit costs that will be amortized into net periodic postretirement benefit costs in 2014 are estimated as follows (in thousands of dollars):
		2014
	Amortization of prior service credit	$	(7,253	)
	Amortization of transition asset	(143		)
	Amortization of unrecognized losses	1,154
	Estimated amount to be amortized from AOCE into net periodic postretirement benefit costs	$	(6,242	)
Schedule of Assumptions Used	'
	The following assumptions were used to determine net periodic benefit costs at January 1:
		For the Years Ended December 31,
		2013			2012			2011
	Discount rate	4	%		4.5	%		5.6	%
	Expected long-term rate of return on plan assets, net of tax	6	%		6	%		6	%
	Initial healthcare cost trend rate	8	%		8.5	%		9	%
	Ultimate healthcare cost trend rate	5	%		5	%		5	%
	Year ultimate healthcare cost trend rate reached	2019			2019			2019
	The following assumptions were used to determine benefit obligations at December 31:
		2013			2012			2011
	Discount rate	4.9	%		4	%		4.5	%
	Expected long-term rate of return on plan assets, net of tax	5.7	%		6	%		6	%
	Initial healthcare cost trend rate	7.5	%		8	%		8.5	%
	Ultimate healthcare cost trend rate	4.5	%		5	%		5	%
	Year ultimate healthcare cost trend rate reached	2026			2019			2019
Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates	'
	A 1 percentage point change in assumed healthcare cost trend rates would have the following effects on 2013 results (in thousands of dollars):
		1 Percentage Point
		Increase				(Decrease)
	Effect on total service and interest cost	$	2,205			$	(1,777	)
	Effect on postretirement benefit obligation	29,776				(24,196		)
Schedule of Allocation of Plan Assets	'
	The plan's assets are stated at fair value which represents the net asset value of shares held by the plan in the registered investment companies at the quoted market prices (Level 1 input) as of December 31 (in thousands of dollars):
		2013				2012
	Registered investment companies
	Fidelity Spartan U.S. Equity Index Fund	$	67,160			$	51,169
	Vanguard 500 Index Fund	67,931				51,336
	Vanguard Total International Stock	25,034				21,739
	Total Assets	$	160,125			$	124,244
Schedule of Expected Benefit Payments	'
	The Company forecasts the following benefit payments (which include a projection for expected future employee service) for the next ten years (in thousands of dollars):
	Year		Estimated Gross Benefit Payments
	2014		$	5,299
	2015		6,075
	2016		6,952
	2017		8,001
	2018		9,159
	2019-2023		$	65,751

LEASES_Tables

LEASES (Tables)	12 Months Ended
	Dec. 31, 2013
Leases [Abstract]	'
Schedule of Future Minimum Rental Payments for Operating Leases	'
	At December 31, 2013, the approximate future minimum lease payments for all operating leases were as follows (in thousands of dollars):
	Year	Future Minimum Lease Payments
	2014	$	67,993
	2015	56,697
	2016	41,232
	2017	27,657
	2018	17,128
	Thereafter	19,937
	Total minimum payments required	230,644
	Less amounts representing sublease income	(4,353		)
		$	226,291

STOCK_INCENTIVE_PLANS_Tables

STOCK INCENTIVE PLANS (Tables)	12 Months Ended
	Dec. 31, 2013
Disclosure of Share-based Compensation, Stock Options	'
	Transactions involving stock options are summarized as follows:
		Shares Subject to Option			Weighted Average Price Per Share				Options Exercisable
	Outstanding at January 1, 2011	4,881,248			$	77.61			2,486,478
	Granted	520,327			$	149.15
	Exercised	(1,323,883	)		$	63.08
	Canceled or expired	(117,017	)		$	89.18
	Outstanding at December 31, 2011	3,960,675			$	91.53			1,808,667
	Granted	404,111			$	203.96
	Exercised	(972,015	)		$	74.14
	Canceled or expired	(34,055	)		$	105.36
	Outstanding at December 31, 2012	3,358,716			$	109.95			1,629,468
	Granted	348,054			$	245.95
	Exercised	(805,235	)		$	85.75
	Canceled or expired	(51,080	)		$	150.15
	Outstanding at December 31, 2013	2,850,455			$	132.67			1,652,417
Information about stock options excercised	'
	The following table summarizes information about stock options exercised (in thousands of dollars):
			For the years ended December 31,
			2013				2012				2011
	Fair value of options exercised		$	16,407			$	18,120			$	20,933
	Total intrinsic value of options exercised		124,752				126,138				124,441
	Fair value of options vested		20,219				15,551				13,549
	Settlements of options exercised		69,049				72,066				83,504
Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range	'
	Information about stock options outstanding and exercisable as of December 31, 2013, is as follows:
			Options Outstanding													Options Exercisable
						Weighted Average													Weighted Average
	Range of		Number			Remaining		Exercise				Intrinsic				Number			Remaining		Exercise		Intrinsic
	Exercise					Contractual		Price				Value							Contractual		Price		Value
	Prices					Life						(000's)							Life				(000's)
	$48.12 - $78.86		458,381			2.19 years		$	67.44			$	86,183			458,381			2.19 years		$	67.44	$	86,183
	$81.49 - $85.82		637,830			4.66 years		$	83.21			109,838				637,830			4.66 years		$	83.21	109,838
	$91.61 - $110.54		526,054			6.29 years		$	107.24			77,950				526,054			6.29 years		$	107.24	77,950
	$124.93 - $204.24		884,682			7.76 years		$	173.26			72,685				26,730			7.52 years		$	159.78	2,557
	$245.86 - $262.14		343,508			9.31 years		$	245.95			3,254				3,422			9.16 years		$	245.86	33
			2,850,455			6.09 years		$	132.67			$	349,910			1,652,417			4.55 years		$	88.06	$	276,561
Assumptions used to determine fair value of options granted	'
	The fair value of each option granted in 2013, 2012 and 2011 used the following assumptions:
			For the years ended December 31,
			2013		2012		2011
	Risk-free interest rate		0.90%		1.10%		2.60%
	Expected life		6 years		6 years		6 years
	Expected volatility		25.50%		25.90%		24.60%
	Expected dividend yield		1.50%		1.60%		1.80%
Transactions involving performance-based share awards	'
	The following table summarizes the transactions involving performance-based share awards:
		2013							2012							2011
		Shares			Weighted Average Price Per Share				Shares			Weighted Average Price Per Share				Shares			Weighted Average Price Per Share
	Beginning nonvested	117,979			$	141.86			192,740			$	109.16			177,120			$	84.74
	shares outstanding
	Issued	31,553			$	191.36			28,639			$	177.75			96,236			$	127.43
	Canceled	(7,659	)		$	148.25			(1,666	)		$	114.41			(13,056	)		$	87.24
	Vested	(84,340	)		$	130.35			(101,734	)		$	90.47			(67,560	)		$	72.86
	Ending nonvested shares	57,533			$	185.02			117,979			$	141.86			192,740			$	109.16
	outstanding
Activity for restricted stock units	'
	The following table summarizes RSU activity:
		2013						2012						2011
		Shares		Weighted				Shares		Weighted				Shares		Weighted
				Average Price Per Share						Average Price Per Share						Average Price Per Share
	Beginning nonvested units	978,888		$	118.6			1,119,488		$	100.76			1,205,787		$	88.65
	Issued	139,529		$	248.28			152,995		$	204.26			242,212		$	152.55
	Canceled	(54,533	)	$	141.48			(37,972	)	$	123.01			(92,202	)	$	89.57
	Vested	(324,167	)	$	89.62			(255,623	)	$	88.36			(236,309	)	$	86.13
	Ending nonvested units	739,717		$	154.09			978,888		$	118.6			1,119,488		$	100.76
	Fair value of shares vested (in millions)	$29						$23						$20
Activity for stock units related to deferred director fees	'
	The following table summarizes DSU activity (dollars in thousands):
		2013						2012						2011
		Units		Dollars				Units		Dollars				Units		Dollars
	Beginning balance	151,775		$	30,952			142,797		$	26,730			130,377		$	18,006
	Dividends	2,259		559				2,273		454				2,244		350
	Deferred fees	7,337		2,059				9,170		1,871				12,601		1,878
	Retirement distribution	(2,503	)	(507		)		(2,465	)	(461		)		(2,425	)	(335		)
	Unit appreciation	—		—				—		2,358				—		6,831
	Ending balance	158,868		$	33,063			151,775		$	30,952			142,797		$	26,730

CAPITAL_STOCK_Tables

CAPITAL STOCK (Tables)	12 Months Ended
	Dec. 31, 2013
CAPITAL STOCK [Abstract]	'
Schedule of Capital Stock	'
	The Company had no shares of preferred stock outstanding as of December 31, 2013 and 2012. The activity related to outstanding common stock and common stock held in treasury was as follows:
		2013				2012
		Outstanding Common Stock		Treasury Stock		Outstanding Common Stock		Treasury Stock
	Balance at beginning of period	69,478,495		40,180,724		69,962,852		39,696,367
	Exercise of stock options, net of 5,134, and 5,310 shares swapped in stock-for-stock exchange, respectively	800,101		(800,101	)	966,705		(966,705	)
	Settlement of restricted stock units, net of 135,341 and 121,353 shares retained, respectively	232,483		(232,483	)	225,997		(225,997	)
	Settlement of performance share units, net of 39,874 and 23,590 shares retained, respectively	61,860		(61,860	)	44,051		(44,051	)
	Purchase of treasury shares	(1,719,001	)	1,719,001		(1,721,110	)	1,721,110
	Balance at end of period	68,853,938		40,805,281		69,478,495		40,180,724

ACCUMULATED_OTHER_COMPREHENSIV1

ACCUMULATED OTHER COMPREHENSIVE EARNINGS (Tables)	12 Months Ended
	Dec. 31, 2013
ACCUMULATED OTHER COMPREHENSIVE EARNINGS [Abstract]	'
Schedule of Accumulated Other Comprehensive Income (Loss)	'
	The following table sets forth the components of Accumulated other comprehensive earnings (in thousands of dollars):
		As of December 31,
		2013			2012
	Foreign currency translation adjustments	$	2,900		$	85,231
	Derivative instruments	(1,944		)	(11,965		)
	Postretirement benefit plan	56,693			3,847
	Other employment-related benefit plans	(11,467		)	(9,835		)
	Deferred tax (liability) asset	(30,374		)	(11,184		)
	Total accumulated other comprehensive earnings	15,808			56,094
	Less: Foreign currency translation adjustments attributable to noncontrolling interest	(13,106		)	2,516
	Total accumulated other comprehensive earnings attributable to W.W. Grainger, Inc.	$	28,914		$	53,578

INCOME_TAXES_Tables

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2013
INCOME TAXES [Abstract]	'
Schedule of Components of Income Tax Expense (Benefit)	'
	Income tax expense consisted of the following (in thousands of dollars):
		For the Years Ended December 31,
		2013			2012			2011
	Current provision:
	Federal	$	398,593		$	324,848		$	275,489
	State	42,526			40,508			49,098
	Foreign	52,277			53,564			45,405
	Total current	493,396			418,920			369,992
	Deferred tax provision (benefit)	(13,546		)	20			15,123
	Total provision	$	479,850		$	418,940		$	385,115
Schedule of Income before Income Tax, Domestic and Foreign	'
	Earnings before income taxes by geographical area consisted of the following (in thousands of dollars):
		For the Years Ended December 31,
		2013			2012			2011
	United States	$	1,167,558		$	982,220		$	917,820
	Foreign	120,041			135,569			133,707
		$	1,287,599		$	1,117,789		$	1,051,527
Schedule of Deferred Tax Assets and Liabilities	'
	The income tax effects of temporary differences that gave rise to the net deferred tax asset were (in thousands of dollars):
		As of December 31,
		2013			2012
	Deferred tax assets:
	Inventory	$	35,381		$	30,991
	Accrued expenses	38,368			26,706
	Accrued employment-related benefits	123,555			139,931
	Foreign operating loss carryforwards	70,204			67,148
	Other	30,862			31,008
	Deferred tax assets	298,370			295,784
	Less valuation allowance	(62,825		)	(54,434		)
	Deferred tax assets, net of valuation allowance	$	235,545		$	241,350
	Deferred tax liabilities:
	Property, buildings and equipment	(38,210		)	(37,876		)
	Intangibles	(119,923		)	(114,955		)
	Software	(17,492		)	(16,653		)
	Prepaids	(18,945		)	(20,509		)
	Other	(17,378		)	(19,291		)
	Deferred tax liabilities	(211,948		)	(209,284		)
	Net deferred tax asset	$	23,597		$	32,066
	The net deferred tax asset is classified as follows:
	Current assets	$	75,819		$	55,967
	Noncurrent assets	16,209			51,536
	Noncurrent liabilities (foreign)	(68,431		)	(75,437		)
	Net deferred tax asset	$	23,597		$	32,066
Reconciliation of Valuation Allowance	'
	The changes in the valuation allowance were as follows (in thousands of dollars):
		For the Years Ended December 31,
		2013			2012
	Beginning balance	$	54,434		$	53,739
	Increase related to foreign net operating loss carryforwards	8,391			695
	Ending balance	$	62,825		$	54,434
Reconciliation of Income Tax Statutory Disclosure	'
	A reconciliation of income tax expense with federal income taxes at the statutory rate follows (in thousands of dollars):
		For the Years Ended December 31,
		2013			2012			2011
	Federal income tax at the 35% statutory rate	$	450,660		$	391,226		$	368,034
	State income taxes, net of federal income tax benefit	27,430			26,099			32,226
	Other - net	1,760			1,615			(15,145		)
	Income tax expense	$	479,850		$	418,940		$	385,115
	Effective tax rate	37.3		%	37.5		%	36.6		%
Reconciliation of Income Tax Contingencies	'
	The changes in the liability for tax uncertainties, excluding interest, are as follows (in thousands of dollars):
		2013			2012
	Balance at beginning of year	$	40,937		$	22,760
	Additions to tax positions related to the current year	8,396			11,369
	Additions for tax positions of prior years	2,308			8,977
	Reductions for tax positions of prior years	(7,242		)	(1,447		)
	Reductions due to statute lapse	(18		)	(737		)
	Settlements, audit payments, refunds - net	(4,064		)	15
	Balance at end of year	$	40,317		$	40,937

EARNINGS_PER_SHARE_Tables

EARNINGS PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2013
Notes to Financial Statements [Abstract]	'
Schedule of Earnings Per Share, Basic and Diluted	'
	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):
		For the Years Ended December 31,
		2013			2012			2011
	Net earnings attributable to W.W. Grainger, Inc. as reported	$	797,036		$	689,881		$	658,423
	Distributed earnings available to participating securities	(3,304		)	(3,641		)	(3,216		)
	Undistributed earnings available to participating securities	(8,348		)	(8,704		)	(9,635		)
	Numerator for basic earnings per share - Undistributed and distributed earnings available to common shareholders	785,384			677,536			645,572
	Undistributed earnings allocated to participating securities	8,348			8,704			9,635
	Undistributed earnings reallocated to participating securities	(8,218		)	(8,540		)	(9,438		)
	Numerator for diluted earnings per share - Undistributed and distributed earnings available to common shareholders	$	785,514		$	677,700		$	645,769
	Denominator for basic earnings per share – weighted average shares	69,455,507			69,811,881			69,690,854
	Effect of dilutive securities	1,120,925			1,369,852			1,485,304
	Denominator for diluted earnings per share – weighted average shares adjusted for dilutive securities	70,576,432			71,181,733			71,176,158
	Earnings per share two-class method
	Basic	$	11.31		$	9.71		$	9.26
	Diluted	$	11.13		$	9.52		$	9.07

SEGMENT_INFORMATION_Tables

SEGMENT INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2013
Notes to Financial Statements [Abstract]	'
Summary of Segment Results	'
	Following is a summary of segment results (in thousands of dollars):
		2013
		United States			Canada			Other Businesses			Total
	Total net sales	$	7,413,712		$	1,114,285		$	1,040,473		$	9,568,470
	Intersegment net sales	(128,660		)	(300		)	(1,752		)	(130,712		)
	Net sales to external customers	7,285,052			1,113,985			1,038,721			9,437,758
	Segment operating earnings	1,304,175			128,768			7,599			1,440,542
	Segment assets	2,045,564			392,147			359,007			2,796,718
	Depreciation and amortization	116,392			14,309			19,754			150,455
	Additions to long-lived assets	$	177,046		$	63,821		$	23,951		$	264,818
		2012
		United States			Canada			Other Businesses			Total
	Total net sales	$	6,925,842		$	1,105,782		$	1,006,762		$	9,038,386
	Intersegment net sales	(87,249		)	(363		)	(729		)	(88,341		)
	Net sales to external customers	6,838,593			1,105,419			1,006,033			8,950,045
	Segment operating earnings	1,132,722			127,412			20,289			1,280,423
	Segment assets	1,884,102			387,915			347,905			2,619,922
	Depreciation and amortization	99,229			14,058			19,202			132,489
	Additions to long-lived assets	$	182,985		$	46,330		$	21,611		$	250,926
		2011
		United States			Canada			Other Businesses			Total
	Total net sales	$	6,501,343		$	992,823		$	647,666		$	8,141,832
	Intersegment net sales	(62,766		)	(163		)	(718		)	(63,647		)
	Net sales to external customers	6,438,577			992,660			646,948			8,078,185
	Segment operating earnings	1,066,324			107,582			30,984			1,204,890
	Segment assets	1,845,703			335,900			331,896			2,513,499
	Depreciation and amortization	100,017			12,840			11,035			123,892
	Additions to long-lived assets	$	148,803		$	29,744		$	13,402		$	191,949
Reconciliation of Other Significant Reconciling Items from Segments to Consolidated [Table Text Block]	'
	Following are reconciliations of the segment information with the consolidated totals per the financial statements (in thousands of dollars):
		2013			2012			2011
	Operating earnings:
	Total operating earnings for reportable segments	$	1,440,542		$	1,280,423		$	1,204,890
	Unallocated expenses	(143,688		)	(149,298		)	(152,461		)
	Total consolidated operating earnings	$	1,296,854		$	1,131,125		$	1,052,429
	Assets:
	Assets for reportable segments	$	2,796,718		$	2,619,922		$	2,513,499
	Other current and noncurrent assets	2,118,298			1,967,480			1,749,029
	Unallocated assets	351,312			427,196			453,534
	Total consolidated assets	$	5,266,328		$	5,014,598		$	4,716,062
		2013
		Segment			Unallocated			Consolidated Total
		Totals
	Other significant items:
	Depreciation and amortization	$	150,455		$	14,447		$	164,902
	Additions to long-lived assets	$	264,818		$	12,782		$	277,600
					Revenues			Long-lived Assets
	Geographic information:
	United States				$	7,290,746		$	1,004,806
	Canada				1,126,559			176,491
	Other foreign countries				1,020,453			134,535
					$	9,437,758		$	1,315,832
		2012
		Segment			Unallocated			Consolidated Total
		Totals
	Other significant items:
	Depreciation and amortization	$	132,489		$	13,123		$	145,612
	Additions to long-lived assets	$	250,926		$	6,998		$	257,924
					Revenues			Long-lived Assets
	Geographic information:
	United States				$	6,786,361		$	944,400
	Canada				1,120,470			136,644
	Other foreign countries				1,043,214			135,438
					$	8,950,045		$	1,216,482
		2011
		Segment			Unallocated			Consolidated Total
		Totals
	Other significant items:
	Depreciation and amortization	$	123,892		$	13,319		$	137,211
	Additions to long-lived assets	$	191,949		$	5,665		$	197,614
					Revenues			Long-lived Assets
	Geographic information:
	United States				$	6,388,506		$	872,947
	Canada				998,014			102,085
	Other foreign countries				691,665			129,014
					$	8,078,185		$	1,104,046

SELECTED_QUARTERLY_FINANCIAL_D1

SELECTED QUARTERLY FINANCIAL DATA (Tables)	12 Months Ended
	Dec. 31, 2013
SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) [Abstract]	'
Schedule of Quarterly Financial Information	'
	A summary of selected quarterly information for 2013 and 2012 is as follows (in thousands of dollars, except for per share amounts):
		2013 Quarter Ended
		31-Mar		30-Jun		30-Sep		31-Dec		Total
	Net sales	$	2,280,435	$	2,381,561	$	2,398,530	$	2,377,232	$	9,437,758
	Cost of merchandise sold	1,248,699		1,334,577		1,347,164		1,370,835		5,301,275
	Gross profit	1,031,736		1,046,984		1,051,366		1,006,397		4,136,483
	Warehousing, marketing and	688,431		696,912		704,651		749,635		2,839,629
	administrative expenses
	Operating earnings	343,305		350,072		346,715		256,762		1,296,854
	Net earnings attributable to W.W. Grainger, Inc.	211,838		217,660		210,789		156,749		797,036
	Earnings per share - basic	2.99		3.08		2.99		2.24		11.31
	Earnings per share - diluted	$	2.94	$	3.03	$	2.95	$	2.2	$	11.13
		2012 Quarter Ended
		31-Mar		30-Jun		30-Sep		31-Dec		Total
	Net sales	$	2,193,445	$	2,249,275	$	2,281,205	$	2,226,120	$	8,950,045
	Cost of merchandise sold	1,219,113		1,270,932		1,287,245		1,256,595		5,033,885
	Gross profit	974,332		978,343		993,960		969,525		3,916,160
	Warehousing, marketing and	669,971		664,343		739,634		711,087		2,785,035
	administrative expenses
	Operating earnings	304,361		314,000		254,326		258,438		1,131,125
	Net earnings attributable to W.W. Grainger, Inc.	187,516		190,704		155,394		156,267		689,881
	Earnings per share - basic	2.63		2.68		2.19		2.21		9.71
	Earnings per share - diluted (1)	$	2.57	$	2.63	$	2.15	$	2.17	$	9.52

SUMMARY_OF_SIGNIFICANT_ACCOUNT2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2011	Oct. 31, 2011
				MRO Korea Co Ltd [Member]	MRO Korea Co Ltd [Member]
Original Maturity of Cash (days)	'90 days	'	'	'	'
Equity Method Investment Minimum Ownership Percentage	20.00%	'	'	'	'
Equity Method Investment Maximum Ownership Percentage	50.00%	'	'	'	'
Equity Method Investment, Ownership Percentage	'	'	'	'	49.00%
Proceeds from Sales of Business, Affiliate and Productive Assets	'	'	'	$12,000,000	'
Gain (Loss) on Sale of Other Investments	'	'	'	8,000,000	'
After-tax gain on sale	'	'	'	5,000,000	'
eCommerce Revenue	33.00%	'	'	'	'
Service Fee Revenue (less than)	1.00%	'	'	'	'
Advertising expense	178,000,000	173,000,000	145,000,000	'	'
Catalog-related prepaid expenses	36,000,000	46,000,000	'	'	'
Percentage of LIFO Inventory	59.00%	'	'	'	'
Buildings, Structures and Improvements, Useful Life Minimum	10	'	'	'	'
Buildings, Structures and Improvements Useful Life Maximum	30	'	'	'	'
Furniture Fixtures Machinery Equipment Useful Life Minimum	3	'	'	'	'
Furniture Fixtures Machinery Equipment Useful Life Maximum	10	'	'	'	'
Intangibles minimum useful lives	3	'	'	'	'
Intangibles maximum useful lives	22	'	'	'	'
Capitalized Interest Costs	1,000,000	1,000,000	1,000,000	'	'
Long lived assets related impairment charges	400,000	2,000,000	8,000,000	'	'
Capitalized software amortization	23,000,000	16,000,000	19,000,000	'	'
Capitalized software	107,000,000	72,000,000	'	'	'
Warranty reserves	$4,000,000	$4,000,000	'	'	'
Amortization of capitalized software minimum	3	'	'	'	'
Amortization of capitalized software maximum	5	'	'	'	'

BUSINESS_ACQUISITIONS_Details

BUSINESS ACQUISITIONS (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2012	Dec. 31, 2011
	Safety Solutions, Inc. [Member]	Safety Solutions, Inc. [Member]	E&R Industrial, Inc. [Member]	E&R Industrial, Inc. [Member]	Grainger Colombia [Member]	Techni Tool, Inc. [Member]	Anfreixo S.A. [Member]	Fabory [Member]
Business Acquisition [Line Items]	'	'	'	'	'	'	'	'
Business Acquisition, Name of Acquired Entity	'Safety Solutions, Inc.	'	'E&R Industrial Sales, Inc.	'	'Grainger Colombia	'Techni-Tool, Inc.	'AnFreixo S.A.	'Fabory
Business Acquisition, Revenue Reported by Acquired Entity for Last Annual Period	'	$63,000,000	'	$180,000,000	'	'	'	'
Business Acquisition, Description of Acquired Entity	'Safety Solutions is a distributor of safety footwear, supplies and services with a strong focus on the manufacturing sector.	'	'E&R Industrial is a distributor of metalworking, production supplies and MRO materials to manufacturers and industrial customers across the Midwest and Eastern United States.	'	'	'	'	'
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	21,000,000	'	80,000,000	'	'	'	'	'
Business Acquisition, Cost of Acquired Entity, Cash Paid	30,000,000	'	116,000,000	'	10,000,000	43,000,000	25,000,000	358,000,000
Goodwill, After Purchase Price Allocation	'	'	'	'	'	10,000,000	11,000,000	140,000,000
Customer relationships amortization	'	'	'	'	'	'13 years	'	'22 years
Trade Name Amortization	'	'	'	'	'	'3 years	'11 years	'
Second Trade Name Amortization	'	'	'	'	'	'	'15 years	'
Supply Contract Intangible Amortization	'	'	'	'	'	'	'4 years	'
Intangible Assets, After Purchase Price Allocation	'	'	'	'	'	$20,000,000	$9,000,000	$131,000,000

GOODWILL_AND_OTHER_INTANGIBLE_2

GOODWILL AND OTHER INTANGIBLE ASSETS (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill [Line Items]	'	'	'
Balance	$525,467	$543,670	$509,183
Acquisitions	35,820	35,851	'
Purchase price adjustments	-10,833	4,523	'
Goodwill, Impairment Loss	-24,121	-4,177	'
Goodwill, Translation Adjustments	-19,069	-1,710	'
United States [Member]	'	'	'
Goodwill [Line Items]	'	'	'
Balance	180,498	170,439	151,231
Acquisitions	35,820	23,385	'
Purchase price adjustments	-12,900	0	'
Goodwill, Impairment Loss	-12,861	-4,177	'
Goodwill, Translation Adjustments	0	0	'
Canada [Member]	'	'	'
Goodwill [Line Items]	'	'	'
Balance	144,588	154,775	150,645
Acquisitions	0	0	'
Purchase price adjustments	0	0	'
Goodwill, Impairment Loss	0	0	'
Goodwill, Translation Adjustments	-10,187	4,130	'
Other Businesses [Member]	'	'	'
Goodwill [Line Items]	'	'	'
Balance	200,381	218,456	207,307
Acquisitions	0	12,466	'
Purchase price adjustments	2,067	4,523	'
Goodwill, Impairment Loss	-11,260	0	'
Goodwill, Translation Adjustments	-8,882	-5,840	'
Fabory [Member]	'	'	'
Goodwill [Line Items]	'	'	'
Balance	134,000	'	'
Excess over carrying value	17.00%	'	'
Grainger Colombia [Member]	'	'	'
Goodwill [Line Items]	'	'	'
Balance	$14,000	'	'
Excess over carrying value	26.00%	'	'

GOODWILL_AND_OTHER_INTANGIBLE_3

GOODWILL AND OTHER INTANGIBLE ASSETS Intangible assets included in Other assets and intangibles (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Gross carrying amount [Member]	'	'
Amortized customer lists and relationships	$350,760	$279,068
Amortized trademarks, trade names and other	38,670	34,907
Non-amortized trade names	72,790	74,782
Total intangible assets	462,220	388,757
Accumulated amortization [Member]	'	'
Amortized customer lists and relationships	134,889	124,137
Amortized trademarks, trade names and other	23,919	21,885
Non-amortized trade names	0	0
Total intangible assets	158,808	146,022
Net carrying amount [Member]	'	'
Amortized customer lists and relationships	215,871	154,931
Amortized trademarks, trade names and other	14,751	13,022
Non-amortized trade names	72,790	74,782
Total intangible assets	$303,412	$242,735

GOODWILL_AND_OTHER_INTANGIBLE_4

GOODWILL AND OTHER INTANGIBLE ASSETS - Amortization Expense Recognized on Intangible Assets (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill [Line Items]	'	'	'
Customer relationships and lists, minimum	'6 years	'	'
Customer relationships and lists, maximum	'22 years	'	'
Trademarks, tradenames and other, minimum	'3 years	'	'
Trademarks, trade names and other, maximum	'17 years	'	'
Amortization of Intangible Assets	$15	$13	$12

GOODWILL_AND_OTHER_INTANGIBLE_5

GOODWILL AND OTHER INTANGIBLE ASSETS Estimated amortization expense (Details) (USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Goodwill [Line Items]	'
2014	$20,257
2015	20,057
2016	18,587
2017	17,630
2018	16,580
Thereafter	$137,511

ALLOWANCE_FOR_DOUBTFUL_ACCOUNT2

ALLOWANCE FOR DOUBTFUL ACCOUNTS (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
ALLOWANCE FOR DOUBTFUL ACCOUNTS [Abstract]	'	'	'
Balance at beginning of period	$19,449	$18,801	'
Provision for uncollectible accounts	8,855	9,504	4,761
Write-off of uncollectible accounts, net of recoveries	-7,942	-9,100	'
Business acquisitions, foreign currency and other	-266	244	'
Balance at end of period	$20,096	$19,449	$18,801

INVENTORIES_Details

INVENTORIES (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
INVENTORIES [Abstract]	'	'	'
Inventory, LIFO Reserve	$388	$376	'
Inventory, LIFO Reserve, Effect on Income, Net	8	13	11
Inventory Valuation Reserves	$134	$133	'

SHORTTERM_DEBT_Details

SHORT-TERM DEBT (Details) (USD $)	60 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Aug. 21, 2018	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
		Lines of Credit [Member]	Lines of Credit [Member]	Letter of Credit [Member]	Letter of Credit [Member]
Short-term Debt [Line Items]	'	'	'	'	'
Lines of credit	'	$67	$79	'	'
Uncommitted lines of credit	'	109	138	'	'
Short-term Debt, Maximum Month-end Outstanding Amount	'	77	79	'	'
Weighted average interest rates during the year	'	4.96%	5.16%	'	'
Short-term Debt, Weighted Average Interest Rate	'	5.02%	5.07%	'	'
Line of Credit Facility, Maximum Borrowing Capacity	'	600	400	'	'
Debt Instrument, Collateral Fee	'	0.06%	0.10%	'	'
Line of Credit Facility, Expiration Date	21-Aug-18	'	'	'	'
Letters Of Credit Outstanding Primarily Related To Insurance Program	'	'	'	26	21
Letters Of Credit Outstanding To Facitate Purchase Of Products From Foreign Sources	'	'	'	$3	$4

LONGTERM_DEBT_Details

LONG-TERM DEBT (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	31-May-12	Dec. 31, 2013	Dec. 31, 2013	Aug. 31, 2016	Aug. 31, 2011
			Bank term loan [Member]	Bank term loan [Member]	Euro denominated bank term loan [Member]	Euro denominated bank term loan [Member]	Euro denominated bank term loan [Member]
Debt Instrument [Line Items]	'	'	'	'	'	'	'
Debt Instrument, Face Amount	'	'	$300,000,000	'	'	'	$120,000,000
Bank term loan	292,500,000	300,000,000	'	'	'	'	'
Euro denominated bank term loan	158,067,000	158,328,000	'	'	'	'	'
Other Long-term Debt	25,375,000	27,245,000	'	'	'	'	'
Long-term Debt	445,513,000	467,048,000	'	'	'	'	'
Current maturities of long-term debt	-30,429,000	-18,525,000	'	'	'	'	'
Debt Instrument, Maturity Date	'	'	30-Nov-16	'	'	31-Aug-16	'
Semi annual payments	'	'	'	'	2,500,000	'	'
Payment start date	'	'	'	31-Aug-13	28-Feb-13	'	'
2015	35,124,000	'	'	'	'	'	'
2016	393,886,000	'	'	'	'	'	'
2017	1,392,000	'	'	'	'	'	'
2018	1,106,000	'	'	'	'	'	'
Thereafter	$14,005,000	'	'	'	'	'	'
Weighted average interest rates during the year	'	'	'	1.19%	1.70%	'	'

DERIVATIVE_INSTRUMENTS_Details

DERIVATIVE INSTRUMENTS (Details)	59 Months Ended				45 Months Ended
In Millions, unless otherwise specified	Aug. 31, 2016	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2012
	Euro denominated interest Rate Swap [Member]	Euro denominated interest Rate Swap [Member]	Euro denominated interest Rate Swap [Member]	Euro denominated interest Rate Swap [Member]	Foreign Exchange Forward [Member]	Foreign Exchange Forward [Member]	Foreign Exchange Forward [Member]	Foreign Exchange Forward [Member]
		USD ($)	EUR (€)	USD ($)		USD ($)	CAD	USD ($)
Derivative [Line Items]	'	'	'	'	'	'	'	'
Derivative instruments, Liabilities	'	$3	'	$4	'	'	'	$8
Derivative instruments, Assets	'	'	'	'	'	1	'	'
Forward foreign currency exchange contract details [Abstract]	'	'	'	'	'	'	'	'
Derivative, notional amount	'	'	€ 60	'	'	'	160	'
Derivative, maturity date	31-Aug-16	'	'	'	30-Sep-14	'	'	'

EMPLOYEE_BENEFITS_Defined_Cont

EMPLOYEE BENEFITS - Defined Contribution Plans (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Minimum profit sharing contribution percentage	8.00%	'	'
Maximum profit sharing contribution percentage	18.00%	'	'
Profit sharing plan expense	$173,000,000	$165,000,000	$156,000,000
Defined contribution plans, expense	12,000,000	12,000,000	9,000,000
Netherlands	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Defined Benefit Plan, Career Pay Percentage	1.75%	'	'
Defined Benefit Plan, Fair Value of Plan Assets	$5,000,000	$6,000,000	'

EMPLOYEE_BENEFITS_Executive_De

EMPLOYEE BENEFITS - Executive Death Benefit Plan (Details) (Executive Death Benefit Plan [Member], USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2010
Executive Death Benefit Plan [Member]	'	'	'
Defined Benefit Plan, Income Contiuation Rate	50.00%	'	'
Net periodic benefit costs	$800	$1,000	$1,000
Net (gains) losses	-1,000	200	'
Defined Benefit Plan, Benefit Obligation	$15,000	$17,000	'

EMPLOYEE_BENEFITS_Postretireme

EMPLOYEE BENEFITS - Postretirement Benefits (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	years
Postretirement obligation decrease from plan changes	'	$84,000,000	'
Reduction in accumulated postretirement benefit obligation due to Medicare Act prescription drug subsidy	'	'	68,000,000
Reduction in net periodic benefits cost due to Medicare Act prescription drug subsidy	'	9,000,000	7,000,000
Other Postretirement Benefit Plans, Defined Benefit [Member]	'	'	'
Postretirement Benefits	'	'	'
Service cost	10,589,000	20,058,000	15,762,000
Interest cost	8,938,000	12,810,000	13,352,000
Expected return on assets	-7,076,000	-6,210,000	-5,790,000
Amortization of prior service credits	-7,412,000	-495,000	-495,000
Amortization of transition asset	-143,000	-143,000	-143,000
Amortization of unrecognized losses	3,724,000	4,827,000	3,269,000
Net periodic benefit costs	8,620,000	30,847,000	25,955,000
Net Unrecognized Losses Amortization Period	15.6	'	'
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]	'	'	'
Benefit obligation at beginning of year	246,087,000	328,912,000	'
Service cost	10,589,000	20,058,000	15,762,000
Interest cost	8,938,000	12,810,000	13,352,000
Plan participants' contributions	2,289,000	2,150,000	'
Plan amendment	0	-84,004,000	'
Actuarial (gains) losses	-38,476,000	-28,234,000	'
Benefits paid	-6,021,000	-6,047,000	'
Medicare Part D Subsidy received	82,000	442,000	'
Benefit obligation at end of year	223,488,000	246,087,000	328,912,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]	'	'	'
Plan assets available for benefits at beginning of year	117,939,000	103,519,000	'
Actual returns (losses) on plan assets	25,278,000	13,355,000	'
Employer's contributions	5,029,000	4,962,000	'
Plan participants' contributions	2,289,000	2,150,000	'
Benefits paid	-6,021,000	-6,047,000	'
Plan assets available for benefits at end of year	144,514,000	117,939,000	103,519,000
Noncurrent postretirement benefit obligation	78,974,000	128,148,000	'
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]	'	'	'
Prior service credit (cost)	74,556,000	81,968,000	'
Transition asset	143,000	286,000	'
Unrecognized losses	-18,006,000	-78,407,000	'
Deferred tax (liability) asset	-21,806,000	-1,618,000	'
Net losses	34,887,000	2,229,000	'
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]	'	'	'
Amortization of prior service credit	-7,253,000	'	'
Amortization of transition asset	-143,000	'	'
Amortization of unrecognized losses	1,154,000	'	'
Estimated amount to be amortized from AOCE into net periodic postretirement benefit costs	-6,242,000	'	'
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]	'	'	'
Discount rate	4.00%	4.50%	5.60%
Expected long-term rate of return on plan assets, net of tax	6.00%	6.00%	6.00%
Initial healthcare cost trend rate	8.00%	8.50%	9.00%
Ultimate healthcare cost trend rate	5.00%	5.00%	5.00%
Year ultimate healthcare cost trend rate reached	'2019	'2019	'2019
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]	'	'	'
Discount rate	4.90%	4.00%	4.50%
Expected long-term rate of return on plan assets, net of tax	5.70%	6.00%	6.00%
Initial healthcare cost trend rate	7.50%	8.00%	8.50%
Ultimate healthcare cost trend rate	4.50%	5.00%	5.00%
Year ultimate healthcare cost trend rate reached	'2026	'2019	'2019
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract]	'	'	'
Effect of one percentage point increase on service and interest cost	2,205,000	'	'
Effect of one percentage point decrease on service and interest cost	-1,777,000	'	'
Effect of one percentage point increase on postretirement benefit obligation	29,776,000	'	'
Effect of one percentage point decrease on postretirement benefit obligation	-24,196,000	'	'
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]	'	'	'
Estimated gross benefit payments, 2014	5,299,000	'	'
Estimated gross benefit payments, 2015	6,075,000	'	'
Estimated gross benefit payments, 2016	6,952,000	'	'
Estimated gross benefit payments, 2017	8,001,000	'	'
Estimated gross benefit payments, 2018	9,159,000	'	'
Estimated gross benefit payments, 2019-2023	65,751,000	'	'
Fidelity Spartan Us Equity Index Fund [Member] | Fair Value, Inputs, Level 1 [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]	'	'	'
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]	'	'	'
Plan assets available for benefits at end of year	67,160,000	51,169,000	'
Vanguard 500 Index Fund [Member] | Fair Value, Inputs, Level 1 [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]	'	'	'
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]	'	'	'
Plan assets available for benefits at end of year	67,931,000	51,336,000	'
Vanguard Total International Stock Member | Fair Value, Inputs, Level 1 [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]	'	'	'
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]	'	'	'
Plan assets available for benefits at end of year	25,034,000	21,739,000	'
Total Registered Investment Companies [Member] | Fair Value, Inputs, Level 1 [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]	'	'	'
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]	'	'	'
Plan assets available for benefits at end of year	160,125,000	124,244,000	'
Medicare benefits [Member]	'	'	'
Obligation decrease due to EGWP	'	$19,000,000	'

LEASES_Details

LEASES (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating Leased Assets [Line Items]	'	'	'
Operating Lease Expiration Date	'2036	'	'
2014	$67,993,000	'	'
2015	56,697,000	'	'
2016	41,232,000	'	'
2017	27,657,000	'	'
2018	17,128,000	'	'
Thereafter	19,937,000	'	'
Total minimum payments required	230,644,000	'	'
Less amounts representing sublease income	-4,353,000	'	'
Operating Leases Future Minimum Payments Net of Income	226,291,000	'	'
Operating Leases, Rent Expense	68,000,000	68,000,000	72,000,000
Operating Leases, Rent Expense, Sublease Rentals	$1,000,000	$1,000,000	$2,000,000

STOCK_INCENTIVE_PLANS_Details

STOCK INCENTIVE PLANS (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Shares of common stock reserved for issuance under 2010 incentive plan (in shares)	5,900,000	'	'
Shares of common stock available for grant under 2010 incentive plan (in shares)	1,900,000	'	'
Share-based compensation excluding dividends	$52,000,000	$53,000,000	$51,000,000
Income tax benefits recognized in earnings for stock-based compensation expense	17,000,000	18,000,000	18,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]	'	'	'
Outstanding at January 1 (in shares)	3,358,716	3,960,675	4,881,248
Granted (in shares)	348,054	404,111	520,327
Exercised (in shares)	-805,235	-972,015	-1,323,883
Canceled or expired (in shares)	-51,080	-34,055	-117,017
Outstanding at December 31 (in shares)	2,850,455	3,358,716	3,960,675
Weighted Average Price Per Share [Abstract]	'	'	'
Outstanding at January 1, weighted average price per share (in dollars per share)	$109.95	$91.53	$77.61
Granted, weighted average price per share (in dollars per share)	$245.95	$203.96	$149.15
Exercised, weighted average price per share (in dollars per share)	$85.75	$74.14	$63.08
Canceled or expired, weighted average price per share (in dollars per share)	$150.15	$105.36	$89.18
Outstanding at December 31, weighted average price per share (in dollars per share)	$132.67	$109.95	$91.53
Options exercisable outstanding at January 1 (in shares)	1,629,468	1,808,667	2,486,478
Options exercisable outstanding at December 31 (in shares)	1,652,417	1,629,468	1,808,667
Stock Options Exercised [Abstract]	'	'	'
Fair value of options exercised	16,407,000	18,120,000	20,933,000
Total intrinsic value of options exercised	124,752,000	126,138,000	124,441,000
Fair value of options vested	20,219,000	15,551,000	13,549,000
Settlements of options exercised	69,049,000	72,066,000	83,504,000
Board Of Directors Deferred Stock Unit Grants To Common Stock Conversion Features Current	125,000	115,000	115,000
Stock Options [Member]	'	'	'
Stock Options Exercised [Abstract]	'	'	'
Unearned unrecognized compensation	$13,000,000	'	'
Weighted average period to recognize (in years)	'1 year 10 months 24 days	'	'

STOCK_INCENTIVE_PLANS_Stock_Op

STOCK INCENTIVE PLANS - Stock Options Outstanding and Exercisable (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	2,850,455	3,358,716	3,960,675	4,881,248
Options outstanding, weighted-average remaining contractual life (in years)	'6 years 1 month 2 days	'	'	'
Options outstanding, weighted-average exercise price (in dollars per share)	$132.67	'	'	'
Options outstanding intrinsic value	$349,910	'	'	'
Options exercisable (in shares)	1,652,417	'	'	'
Options exercisable, weighted-average remaining contractual life (in years)	'4 years 6 months 19 days	'	'	'
Options exercisable, weighted-average exercise price (in dollars per share)	$88.06	'	'	'
Options exercisable intrinsic value	276,561	'	'	'
Range 1 of Exercise Prices [Member]	'	'	'	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'	'	'
Exercise price range, lower range limit (in dollars per share)	$48.12	'	'	'
Exercise price range, upper range limit (in dollars per share)	$78.86	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	458,381	'	'	'
Options outstanding, weighted-average remaining contractual life (in years)	'2 years 2 months 9 days	'	'	'
Options outstanding, weighted-average exercise price (in dollars per share)	$67.44	'	'	'
Options outstanding intrinsic value	86,183	'	'	'
Options exercisable (in shares)	458,381	'	'	'
Options exercisable, weighted-average remaining contractual life (in years)	'2 years 2 months 9 days	'	'	'
Options exercisable, weighted-average exercise price (in dollars per share)	$67.44	'	'	'
Options exercisable intrinsic value	86,183	'	'	'
Range 2 of Exercise Prices [Member]	'	'	'	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'	'	'
Exercise price range, lower range limit (in dollars per share)	$81.49	'	'	'
Exercise price range, upper range limit (in dollars per share)	$85.82	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	637,830	'	'	'
Options outstanding, weighted-average remaining contractual life (in years)	'4 years 7 months 28 days	'	'	'
Options outstanding, weighted-average exercise price (in dollars per share)	$83.21	'	'	'
Options outstanding intrinsic value	109,838	'	'	'
Options exercisable (in shares)	637,830	'	'	'
Options exercisable, weighted-average remaining contractual life (in years)	'4 years 7 months 28 days	'	'	'
Options exercisable, weighted-average exercise price (in dollars per share)	$83.21	'	'	'
Options exercisable intrinsic value	109,838	'	'	'
Range 3 of Exercise Prices [Member]	'	'	'	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'	'	'
Exercise price range, lower range limit (in dollars per share)	$91.61	'	'	'
Exercise price range, upper range limit (in dollars per share)	$110.54	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	526,054	'	'	'
Options outstanding, weighted-average remaining contractual life (in years)	'6 years 3 months 15 days	'	'	'
Options outstanding, weighted-average exercise price (in dollars per share)	$107.24	'	'	'
Options outstanding intrinsic value	77,950	'	'	'
Options exercisable (in shares)	526,054	'	'	'
Options exercisable, weighted-average remaining contractual life (in years)	'6 years 3 months 15 days	'	'	'
Options exercisable, weighted-average exercise price (in dollars per share)	$107.24	'	'	'
Options exercisable intrinsic value	77,950	'	'	'
Range 4 of Exercise Prices [Member]	'	'	'	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'	'	'
Exercise price range, lower range limit (in dollars per share)	$124.93	'	'	'
Exercise price range, upper range limit (in dollars per share)	$204.24	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	884,682	'	'	'
Options outstanding, weighted-average remaining contractual life (in years)	'7 years 9 months 3 days	'	'	'
Options outstanding, weighted-average exercise price (in dollars per share)	$173.26	'	'	'
Options outstanding intrinsic value	72,685	'	'	'
Options exercisable (in shares)	26,730	'	'	'
Options exercisable, weighted-average remaining contractual life (in years)	'7 years 6 months 7 days	'	'	'
Options exercisable, weighted-average exercise price (in dollars per share)	$159.78	'	'	'
Options exercisable intrinsic value	2,557	'	'	'
Range 5 of Exercise Prices [Member]	'	'	'	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'	'	'
Exercise price range, lower range limit (in dollars per share)	$245.86	'	'	'
Exercise price range, upper range limit (in dollars per share)	$262.14	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	343,508	'	'	'
Options outstanding, weighted-average remaining contractual life (in years)	'9 years 3 months 22 days	'	'	'
Options outstanding, weighted-average exercise price (in dollars per share)	$245.95	'	'	'
Options outstanding intrinsic value	3,254	'	'	'
Options exercisable (in shares)	3,422	'	'	'
Options exercisable, weighted-average remaining contractual life (in years)	'9 years 1 month 27 days	'	'	'
Options exercisable, weighted-average exercise price (in dollars per share)	$245.86	'	'	'
Options exercisable intrinsic value	$33	'	'	'

STOCK_INCENTIVE_PLANS_Fair_Val

STOCK INCENTIVE PLANS - Fair Value of Options (Details) (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Weighted average fair value of options granted	$51.30	$43.98	$33.95
Risk-free interest rate (in hundredths)	0.90%	1.10%	2.60%
Expected life (in years)	'6 years	'6 years	'6 years
Expected volatility (in hundredths)	25.50%	25.90%	24.60%
Expected dividend yield (in hundredths)	1.50%	1.60%	1.80%
Stock Options [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$13	'	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	'1 year 10 months 24 days	'	'

STOCK_INCENTIVE_PLANS_Performa

STOCK INCENTIVE PLANS - Performance Shares and Restricted Stock Units (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Performance Shares [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]	'	'	'
Outstanding at beginning of period (in shares)	117,979	192,740	177,120
Issued (in shares)	31,553	28,639	96,236
Cancelled (in shares)	-7,659	-1,666	-13,056
Vested (in shares)	-84,340	-101,734	-67,560
Outstanding at end of period (in shares)	57,533	117,979	192,740
Weighted Average Price Per Share [Abstract]	'	'	'
Outstanding at beginning of period, weighted average price per share (in dollars per share)	$141.86	$109.16	$84.74
Issued, weighted average price per share (in dollars per share)	$191.36	$177.75	$127.43
Cancelled, weighted average price per share (in dollars per share)	$148.25	$114.41	$87.24
Vested, weighted average price per share (in dollars per share)	$130.35	$90.47	$72.86
Outstanding at end of period, weighted average price per share (in dollars per share)	$185.02	$141.86	$109.16
Unearned unrecognized compensation	$5	'	'
Weighted average period to recognize (in years)	'1 year 8 months 13 days	'	'
Restricted Stock Units [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Share-Based Compensation Vested Fair Value	29	23	20
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]	'	'	'
Outstanding at beginning of period (in shares)	978,888	1,119,488	1,205,787
Issued (in shares)	139,529	152,995	242,212
Cancelled (in shares)	-54,533	-37,972	-92,202
Vested (in shares)	-324,167	-255,623	-236,309
Outstanding at end of period (in shares)	739,717	978,888	1,119,488
Weighted Average Price Per Share [Abstract]	'	'	'
Outstanding at beginning of period, weighted average price per share (in dollars per share)	$118.60	$100.76	$88.65
Issued, weighted average price per share (in dollars per share)	$248.28	$204.26	$152.55
Cancelled, weighted average price per share (in dollars per share)	$141.48	$123.01	$89.57
Vested, weighted average price per share (in dollars per share)	$89.62	$88.36	$86.13
Outstanding at end of period, weighted average price per share (in dollars per share)	$154.09	$118.60	$100.76
Unearned unrecognized compensation	$54	'	'
Weighted average period to recognize (in years)	'3 years 3 months 19 days	'	'

STOCK_INCENTIVE_PLANS_Director

STOCK INCENTIVE PLANS - Director Stock Awards (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Director stock awards	'	'	'
Deferred stock units (DSU) granted	$125,000	$115,000	$115,000
Directors' deferred stock unit grants	'	'	'
Beginning balance (in shares)	151,775	142,797	130,377
Dividends (in shares)	2,259	2,273	2,244
Deferred fees (in shares)	7,337	9,170	12,601
Retirement distribution (in shares)	-2,503	-2,465	-2,425
Unit appreciation (in shares)	0	0	0
Ending balance (in shares)	158,868	151,775	142,797
Beginning balance	30,952,000	26,730,000	18,006,000
Dividends	559,000	454,000	350,000
Deferred fees	2,059,000	1,871,000	1,878,000
Retirement distribution	-507,000	-461,000	-335,000
Unit appreciation	0	2,358,000	6,831,000
Ending balance	$33,063,000	$30,952,000	$26,730,000

CAPITAL_STOCK_Details

CAPITAL STOCK (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Treasury Stock, Shares	40,805,281	40,180,724	'
Exercised (in shares)	-805,235	-972,015	-1,323,883
Common Stock [Member]	'	'	'
Common Stock, Shares, Outstanding	68,853,938	69,478,495	69,962,852
Settlement of restricted stock units, net of 135,341 and 121,353 shares retained, respectively	232,483	225,997	'
Settlement of performance share units, net of 39,874 and 23,590 shares retained, respectively	61,860	44,051	'
Purchase of treasury shares	-1,719,001	-1,721,110	'
Treasury Stock [Member]	'	'	'
Treasury Stock, Shares	40,805,281	40,180,724	39,696,367
Settlement of restricted stock units, net of 135,341 and 121,353 shares retained, respectively	-232,483	-225,997	'
Settlement of performance share units, net of 39,874 and 23,590 shares retained, respectively	-61,860	-44,051	'
Purchase of treasury shares	1,719,001	1,721,110	'
Exercise of stock options, net of 5,134, and 5,310 shares swapped in stock-for-stock exchange, respectively | Common Stock [Member]	'	'	'
Exercised (in shares)	800,101	966,705	'
Exercise of stock options, net of 5,134, and 5,310 shares swapped in stock-for-stock exchange, respectively | Treasury Stock [Member]	'	'	'
Exercised (in shares)	-800,101	-966,705	'

ACCUMULATED_OTHER_COMPREHENSIV2

ACCUMULATED OTHER COMPREHENSIVE EARNINGS (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Foreign currency translation adjustments	$2,900	$85,231
Derivative instruments	-1,944	-11,965
Postretirement benefit plan	56,693	3,847
Other employment-related benefit plans	-11,467	-9,835
Deferred tax (liability) asset	-30,374	-11,184
Total accumulated other comprehensive earnings	15,808	56,094
Less: Foreign currency translation adjustments attributable to noncontrolling interest	-13,106	2,516
Total accumulated other comprehensive earnings attributable to W.W. Grainger, Inc.	$28,914	$53,578

INCOME_TAXES_Details

INCOME TAXES (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Current provision:	'	'	'
Federal	$398,593,000	$324,848,000	$275,489,000
State	42,526,000	40,508,000	49,098,000
Foreign	52,277,000	53,564,000	45,405,000
Total current	493,396,000	418,920,000	369,992,000
Deferred Income Tax Expense (Benefit)	-13,546,000	20,000	15,123,000
Total provision	479,850,000	418,940,000	385,115,000
Undistributed Foreign Subsidiary Earnings	386,000,000	'	'
Interest benefit (expense)	-2,000,000	-1,000,000	1,000,000
Interest accrued	$4,000,000	$2,000,000	'

INCOME_TAXES_Net_Earnings_Befo

INCOME TAXES - Net Earnings Before Income Taxes by Geographical Area (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net earnings before income taxes by geographical area	'	'	'
United States	$1,167,558	$982,220	$917,820
Foreign	120,041	135,569	133,707
Earnings before income taxes	$1,287,599	$1,117,789	$1,051,527

INCOME_TAXES_Income_Tax_Effect

INCOME TAXES - Income Tax Effects of Temporary Differences (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Deferred tax assets:	'	'	'
Inventory	$35,381,000	$30,991,000	'
Accrued expenses	38,368,000	26,706,000	'
Accrued employment-related benefits	123,555,000	139,931,000	'
Foreign operating loss carryforwards	70,204,000	67,148,000	'
Other	30,862,000	31,008,000	'
Deferred tax assets	298,370,000	295,784,000	'
Less valuation allowance	-62,825,000	-54,434,000	-53,739,000
Deferred tax assets, net of valuation allowance	235,545,000	241,350,000	'
Deferred tax liabilities:	'	'	'
Property, buildings and equipment	-38,210,000	-37,876,000	'
Intangibles	-119,923,000	-114,955,000	'
Software	-17,492,000	-16,653,000	'
Prepaids	-18,945,000	-20,509,000	'
Other	-17,378,000	-19,291,000	'
Deferred tax liabilities	-211,948,000	-209,284,000	'
Net deferred tax asset	23,597,000	32,066,000	'
The net deferred tax asset is classified as follows:	'	'	'
Current assets	75,819,000	55,967,000	'
Noncurrent assets	16,209,000	51,536,000	'
Noncurrent liabilities (foreign)	-68,431,000	-75,437,000	'
Operating loss carryforwards related primarily from foreign operations	$262,000,000	'	'

INCOME_TAXES_Changes_in_the_Va

INCOME TAXES - Changes in the Valuation Allowance (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred Tax Asset Valuation Allowance Roll [Forward]	'	'
Beginning balance	$54,434	$53,739
Increase related to foreign net operating loss carryforwards	8,391	695
Ending balance	$62,825	$54,434

INCOME_TAXES_Reconciliation_of

INCOME TAXES - Reconciliation of Income Tax Expense with Federal Income Taxes at the Statutory Rate (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of income tax expense with federal income taxes at the statutory rate	'	'	'
Federal income tax at the 35% statutory rate	$450,660	$391,226	$368,034
State income taxes, net of federal income tax benefit	27,430	26,099	32,226
Other - net	1,760	1,615	-15,145
Total provision	$479,850	$418,940	$385,115
Effective tax rate	37.30%	37.50%	36.60%

INCOME_TAXES_Changes_in_Liabil

INCOME TAXES - Changes in Liability for Tax Uncertainties, Excluding Interest (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Changes in liability for tax uncertainties, excluding interest	'	'
Balance at beginning of year	$40,937,000	$22,760,000
Additions to tax positions related to the current year	8,396,000	11,369,000
Additions for tax positions of prior years	2,308,000	8,977,000
Reductions for tax positions of prior years	-7,242,000	-1,447,000
Reductions due to statute lapse	-18,000	-737,000
Settlements, audit payments, refunds - net	-4,064,000	15,000
Balance at end of year	40,317,000	40,937,000
Liability for tax uncertainties	$8,000,000	$6,000,000

EARNINGS_PER_SHARE_Details

EARNINGS PER SHARE (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Notes to Financial Statements [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Net earnings attributable to W.W. Grainger, Inc. as reported	$156,749	$210,789	$217,660	$211,838	$156,267	$155,394	$190,704	$187,516	$797,036	$689,881	$658,423
Distributed earnings available to participating securities	'	'	'	'	'	'	'	'	-3,304	-3,641	-3,216
Undistributed Earnings Available To Participating Securities	'	'	'	'	'	'	'	'	-8,348	-8,704	-9,635
Numerator for basic earnings per share - Undistributed and distributed earnings available to common shareholders	'	'	'	'	'	'	'	'	785,384	677,536	645,572
Undistributed earnings allocated to participating securities	'	'	'	'	'	'	'	'	8,348	8,704	9,635
Undistributed earnings reallocated to participating securities	'	'	'	'	'	'	'	'	-8,218	-8,540	-9,438
Numerator for diluted earnings per share - Undistributed and distributed earnings available to common shareholders	'	'	'	'	'	'	'	'	$785,514	$677,700	$645,769
Denominator for basic earnings per share - weighted average shares (in shares)	'	'	'	'	'	'	'	'	69,455,507	69,811,881	69,690,854
Effect of dilutive securities (in shares)	'	'	'	'	'	'	'	'	1,120,925	1,369,852	1,485,304
Denominator for diluted earnings per share - weighted average shares adjusted for dilutive securities (in shares)	'	'	'	'	'	'	'	'	70,576,432	71,181,733	71,176,158
Earnings per share Two-class method	'	'	'	'	'	'	'	'	'	'	'
Basic (in dollars per share)	$2.24	$2.99	$3.08	$2.99	$2.21	$2.19	$2.68	$2.63	$11.31	$9.71	$9.26
Diluted (in dollars per share)	$2.20	$2.95	$3.03	$2.94	$2.17	$2.15	$2.63	$2.57	$11.13	$9.52	$9.07

SEGMENT_INFORMATION_Details

SEGMENT INFORMATION (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Service Fee Revenue (less than)	'	'	'	'	'	'	'	'	1.00%	'	'
Summarized Information:	'	'	'	'	'	'	'	'	'	'	'
Operating Income	$256,762	$346,715	$350,072	$343,305	$258,438	$254,326	$314,000	$304,361	$1,296,854	$1,131,125	$1,052,429
Total assets	5,266,328	'	'	'	5,014,598	'	'	'	5,266,328	5,014,598	4,716,062
Depreciation, Depletion and Amortization	'	'	'	'	'	'	'	'	164,902	145,612	137,211
Net sales	2,377,232	2,398,530	2,381,561	2,280,435	2,226,120	2,281,205	2,249,275	2,193,445	9,437,758	8,950,045	8,078,185
Segment Reporting Information, Additions to Long-Lived Assets	'	'	'	'	'	'	'	'	277,600	257,924	197,614
Long-lived Assets	1,315,832	'	'	'	1,216,482	'	'	'	1,315,832	1,216,482	1,104,046
United States [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized Information:	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	7,285,052	6,838,593	6,438,577
Canada [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized Information:	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	1,113,985	1,105,419	992,660
Other Businesses [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized Information:	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	1,038,721	1,006,033	646,948
Segment Balances before intersegment eliminations and consolidations [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized Information:	'	'	'	'	'	'	'	'	'	'	'
Operating Income	'	'	'	'	'	'	'	'	1,440,542	1,280,423	1,204,890
Total assets	2,796,718	'	'	'	2,619,922	'	'	'	2,796,718	2,619,922	2,513,499
Depreciation, Depletion and Amortization	'	'	'	'	'	'	'	'	150,455	132,489	123,892
Net sales	'	'	'	'	'	'	'	'	9,568,470	9,038,386	8,141,832
Segment Reporting Information, Additions to Long-Lived Assets	'	'	'	'	'	'	'	'	264,818	250,926	191,949
Segment Balances before intersegment eliminations and consolidations [Member] | United States [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized Information:	'	'	'	'	'	'	'	'	'	'	'
Operating Income	'	'	'	'	'	'	'	'	1,304,175	1,132,722	1,066,324
Total assets	2,045,564	'	'	'	1,884,102	'	'	'	2,045,564	1,884,102	1,845,703
Depreciation, Depletion and Amortization	'	'	'	'	'	'	'	'	116,392	99,229	100,017
Net sales	'	'	'	'	'	'	'	'	7,413,712	6,925,842	6,501,343
Segment Reporting Information, Additions to Long-Lived Assets	'	'	'	'	'	'	'	'	177,046	182,985	148,803
Segment Balances before intersegment eliminations and consolidations [Member] | Canada [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized Information:	'	'	'	'	'	'	'	'	'	'	'
Operating Income	'	'	'	'	'	'	'	'	128,768	127,412	107,582
Total assets	392,147	'	'	'	387,915	'	'	'	392,147	387,915	335,900
Depreciation, Depletion and Amortization	'	'	'	'	'	'	'	'	14,309	14,058	12,840
Net sales	'	'	'	'	'	'	'	'	1,114,285	1,105,782	992,823
Segment Reporting Information, Additions to Long-Lived Assets	'	'	'	'	'	'	'	'	63,821	46,330	29,744
Segment Balances before intersegment eliminations and consolidations [Member] | Other Businesses [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized Information:	'	'	'	'	'	'	'	'	'	'	'
Operating Income	'	'	'	'	'	'	'	'	7,599	20,289	30,984
Total assets	359,007	'	'	'	347,905	'	'	'	359,007	347,905	331,896
Depreciation, Depletion and Amortization	'	'	'	'	'	'	'	'	19,754	19,202	11,035
Net sales	'	'	'	'	'	'	'	'	1,040,473	1,006,762	647,666
Segment Reporting Information, Additions to Long-Lived Assets	'	'	'	'	'	'	'	'	23,951	21,611	13,402
Intersegment Eliminations [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized Information:	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	-130,712	-88,341	-63,647
Intersegment Eliminations [Member] | United States [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized Information:	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	-128,660	-87,249	-62,766
Intersegment Eliminations [Member] | Canada [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized Information:	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	-300	-363	-163
Intersegment Eliminations [Member] | Other Businesses [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized Information:	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	-1,752	-729	-718
Segment other current and noncurrent assets [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized Information:	'	'	'	'	'	'	'	'	'	'	'
Total assets	2,118,298	'	'	'	1,967,480	'	'	'	2,118,298	1,967,480	1,749,029
Elimination and Unallocated in consolidation [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized Information:	'	'	'	'	'	'	'	'	'	'	'
Operating Income	'	'	'	'	'	'	'	'	-143,688	-149,298	-152,461
Total assets	351,312	'	'	'	427,196	'	'	'	351,312	427,196	453,534
Depreciation, Depletion and Amortization	'	'	'	'	'	'	'	'	14,447	13,123	13,319
Segment Reporting Information, Additions to Long-Lived Assets	'	'	'	'	'	'	'	'	12,782	6,998	5,665
Geographical Information: | United States [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized Information:	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	7,290,746	6,786,361	6,388,506
Long-lived Assets	1,004,806	'	'	'	944,400	'	'	'	1,004,806	944,400	872,947
Geographical Information: | Canada [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized Information:	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	1,126,559	1,120,470	998,014
Long-lived Assets	176,491	'	'	'	136,644	'	'	'	176,491	136,644	102,085
Geographical Information: | Other Foreign Countries [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized Information:	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	1,020,453	1,043,214	691,665
Long-lived Assets	$134,535	'	'	'	$135,438	'	'	'	$134,535	$135,438	$129,014

SELECTED_QUARTERLY_FINANCIAL_D2

SELECTED QUARTERLY FINANCIAL DATA (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net sales	$2,377,232	$2,398,530	$2,381,561	$2,280,435	$2,226,120	$2,281,205	$2,249,275	$2,193,445	$9,437,758	$8,950,045	$8,078,185
Cost of merchandise sold	1,370,835	1,347,164	1,334,577	1,248,699	1,256,595	1,287,245	1,270,932	1,219,113	5,301,275	5,033,885	4,567,393
Gross profit	1,006,397	1,051,366	1,046,984	1,031,736	969,525	993,960	978,343	974,332	4,136,483	3,916,160	3,510,792
Warehousing, marketing and administrative expenses	749,635	704,651	696,912	688,431	711,087	739,634	664,343	669,971	2,839,629	2,785,035	2,458,363
Operating earnings	256,762	346,715	350,072	343,305	258,438	254,326	314,000	304,361	1,296,854	1,131,125	1,052,429
Net earnings attributable to W.W. Grainger, Inc.	$156,749	$210,789	$217,660	$211,838	$156,267	$155,394	$190,704	$187,516	$797,036	$689,881	$658,423
Earnings per share - basic	$2.24	$2.99	$3.08	$2.99	$2.21	$2.19	$2.68	$2.63	$11.31	$9.71	$9.26
Earnings per share - diluted	$2.20	$2.95	$3.03	$2.94	$2.17	$2.15	$2.63	$2.57	$11.13	$9.52	$9.07
Per share expense related to a settlement	'	'	'	'	'	$0.66	'	'	'	'	'

CONTINGENCIES_AND_LEGAL_MATTER1

CONTINGENCIES AND LEGAL MATTERS (Details)	12 Months Ended
	Dec. 31, 2013	Jan. 23, 2014
Loss Contingencies [Line Items]	'	'
Number of new plaintiffs in asbestos and or silica cases filed against the company	70	'
Number of plaintiffs in asbestos and or silica lawsuits whose allegations against the company were dismissed	67	'
Number of plaintiffs in asbestos and or silica cases filed against the company	'	1,929