{
 "instance": {
  "gww20191231-10k.htm": {
   "axisCustom": 1,
   "axisStandard": 23,
   "contextCount": 382,
   "dts": {
    "calculationLink": {
     "local": [
      "gww-20191231_cal.xml"
     ]
    },
    "definitionLink": {
     "local": [
      "gww-20191231_def.xml"
     ],
     "remote": [
      "http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-eedm-def-2019-01-31.xml",
      "http://xbrl.fasb.org/srt/2019/elts/srt-eedm1-def-2019-01-31.xml"
     ]
    },
    "inline": {
     "local": [
      "gww20191231-10k.htm"
     ]
    },
    "labelLink": {
     "local": [
      "gww-20191231_lab.xml"
     ],
     "remote": [
      "http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-doc-2019-01-31.xml",
      "https://xbrl.sec.gov/dei/2019/dei-doc-2019-01-31.xml"
     ]
    },
    "presentationLink": {
     "local": [
      "gww-20191231_pre.xml"
     ]
    },
    "referenceLink": {
     "remote": [
      "https://xbrl.sec.gov/dei/2019/dei-ref-2019-01-31.xml",
      "http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-ref-2019-01-31.xml"
     ]
    },
    "schema": {
     "local": [
      "gww-20191231.xsd"
     ],
     "remote": [
      "http://xbrl.fasb.org/srt/2019/elts/srt-types-2019-01-31.xsd",
      "http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd",
      "http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd",
      "http://www.xbrl.org/2003/xl-2003-12-31.xsd",
      "http://www.xbrl.org/2003/xlink-2003-12-31.xsd",
      "http://www.xbrl.org/dtr/type/numeric-2009-12-16.xsd",
      "http://www.xbrl.org/dtr/type/nonNumeric-2009-12-16.xsd",
      "http://www.xbrl.org/2006/ref-2006-02-27.xsd",
      "http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd",
      "http://www.xbrl.org/2005/xbrldt-2005.xsd",
      "http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd",
      "http://xbrl.fasb.org/us-gaap/2019/elts/us-roles-2019-01-31.xsd",
      "http://xbrl.fasb.org/srt/2019/elts/srt-roles-2019-01-31.xsd",
      "https://xbrl.sec.gov/country/2017/country-2017-01-31.xsd",
      "http://xbrl.fasb.org/us-gaap/2019/elts/us-types-2019-01-31.xsd",
      "http://www.xbrl.org/lrr/arcrole/factExplanatory-2009-12-16.xsd",
      "http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd",
      "http://www.xbrl.org/lrr/role/net-2009-12-16.xsd",
      "https://xbrl.sec.gov/currency/2019/currency-2019-01-31.xsd",
      "https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd",
      "https://xbrl.sec.gov/exch/2019/exch-2019-01-31.xsd",
      "http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd",
      "http://xbrl.sec.gov/naics/2017/naics-2017-01-31.xsd",
      "http://xbrl.sec.gov/sic/2011/sic-2011-01-31.xsd",
      "https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd",
      "http://www.xbrl.org/lrr/role/deprecated-2009-12-16.xsd",
      "http://www.xbrl.org/lrr/role/reference-2009-12-16.xsd",
      "http://xbrl.fasb.org/us-gaap/2019/elts/us-parts-codification-2019-01-31.xsd"
     ]
    }
   },
   "elementCount": 671,
   "entityCount": 1,
   "hidden": {
    "http://fasb.org/us-gaap/2019-01-31": 40,
    "http://www.grainger.com/20191231": 15,
    "http://xbrl.sec.gov/dei/2019-01-31": 5,
    "total": 60
   },
   "keyCustom": 43,
   "keyStandard": 445,
   "memberCustom": 37,
   "memberStandard": 43,
   "nsprefix": "gww",
   "nsuri": "http://www.grainger.com/20191231",
   "report": {
    "R1": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "dei:DocumentType",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "document",
     "isDefault": "true",
     "longName": "0001000 - Document - COVER",
     "role": "http://www.grainger.com/role/Cover",
     "shortName": "COVER",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "dei:DocumentType",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R10": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:SignificantAccountingPoliciesTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2101100 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES",
     "role": "http://www.grainger.com/role/SummaryOfSignificantAccountingPolicies",
     "shortName": "SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:SignificantAccountingPoliciesTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R11": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:RevenueFromContractWithCustomerTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2102100 - Disclosure - REVENUE",
     "role": "http://www.grainger.com/role/Revenue",
     "shortName": "REVENUE",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:RevenueFromContractWithCustomerTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R12": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:PropertyPlantAndEquipmentDisclosureTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2104100 - Disclosure - PROPERTY, BUILDINGS AND EQUIPMENT",
     "role": "http://www.grainger.com/role/PropertyBuildingsAndEquipment",
     "shortName": "PROPERTY, BUILDINGS AND EQUIPMENT",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:PropertyPlantAndEquipmentDisclosureTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R13": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:GoodwillAndIntangibleAssetsDisclosureTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2107100 - Disclosure - GOODWILL AND OTHER INTANGIBLE ASSETS",
     "role": "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssets",
     "shortName": "GOODWILL AND OTHER INTANGIBLE ASSETS",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:GoodwillAndIntangibleAssetsDisclosureTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R14": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:RestructuringAndRelatedActivitiesDisclosureTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2108100 - Disclosure - RESTRUCTURING RESERVES",
     "role": "http://www.grainger.com/role/RestructuringReserves",
     "shortName": "RESTRUCTURING RESERVES",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:RestructuringAndRelatedActivitiesDisclosureTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R15": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ShortTermDebtTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2109100 - Disclosure - SHORT-TERM DEBT",
     "role": "http://www.grainger.com/role/ShortTermDebt",
     "shortName": "SHORT-TERM DEBT",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ShortTermDebtTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R16": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:LongTermDebtTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2111100 - Disclosure - LONG-TERM DEBT",
     "role": "http://www.grainger.com/role/LongTermDebt",
     "shortName": "LONG-TERM DEBT",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:LongTermDebtTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R17": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:PensionAndOtherPostretirementBenefitsDisclosureTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2112100 - Disclosure - EMPLOYEE BENEFITS",
     "role": "http://www.grainger.com/role/EmployeeBenefits",
     "shortName": "EMPLOYEE BENEFITS",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:PensionAndOtherPostretirementBenefitsDisclosureTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R18": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:LesseeOperatingLeasesTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2113100 - Disclosure - LEASES",
     "role": "http://www.grainger.com/role/Leases",
     "shortName": "LEASES",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:LesseeOperatingLeasesTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R19": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2115100 - Disclosure - STOCK INCENTIVE PLANS",
     "role": "http://www.grainger.com/role/StockIncentivePlans",
     "shortName": "STOCK INCENTIVE PLANS",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R2": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax",
      "reportCount": 1,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "statement",
     "isDefault": "false",
     "longName": "1002000 - Statement - CONSOLIDATED STATEMENTS OF EARNINGS",
     "role": "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings",
     "shortName": "CONSOLIDATED STATEMENTS OF EARNINGS",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "-6",
      "lang": null,
      "name": "us-gaap:InterestIncomeExpenseNet",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R20": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "gww:CapitalStockTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2116100 - Disclosure - CAPITAL STOCK",
     "role": "http://www.grainger.com/role/CapitalStock",
     "shortName": "CAPITAL STOCK",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "gww:CapitalStockTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R21": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ComprehensiveIncomeNoteTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2117100 - Disclosure - ACCUMULATED OTHER COMPREHENSIVE EARNINGS (LOSSES) (AOCE)",
     "role": "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoce",
     "shortName": "ACCUMULATED OTHER COMPREHENSIVE EARNINGS (LOSSES) (AOCE)",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ComprehensiveIncomeNoteTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R22": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:IncomeTaxDisclosureTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2118100 - Disclosure - INCOME TAXES",
     "role": "http://www.grainger.com/role/IncomeTaxes",
     "shortName": "INCOME TAXES",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:IncomeTaxDisclosureTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R23": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:SegmentReportingDisclosureTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2119100 - Disclosure - SEGMENT INFORMATION",
     "role": "http://www.grainger.com/role/SegmentInformation",
     "shortName": "SEGMENT INFORMATION",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:SegmentReportingDisclosureTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R24": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:LegalMattersAndContingenciesTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2120100 - Disclosure - CONTINGENCIES AND LEGAL MATTERS",
     "role": "http://www.grainger.com/role/ContingenciesAndLegalMatters",
     "shortName": "CONTINGENCIES AND LEGAL MATTERS",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:LegalMattersAndContingenciesTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R25": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:QuarterlyFinancialInformationTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2121100 - Disclosure - SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED)",
     "role": "http://www.grainger.com/role/SelectedQuarterlyFinancialDataUnaudited",
     "shortName": "SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED)",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:QuarterlyFinancialInformationTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R26": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:SubsequentEventsTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2122100 - Disclosure - SUBSEQUENT EVENT (Notes)",
     "role": "http://www.grainger.com/role/SubsequentEventNotes",
     "shortName": "SUBSEQUENT EVENT (Notes)",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:SubsequentEventsTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R27": {
     "firstAnchor": {
      "ancestors": [
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ConsolidationPolicyTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2201201 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)",
     "role": "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies",
     "shortName": "SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)",
     "subGroupType": "policies",
     "uniqueAnchor": {
      "ancestors": [
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ConsolidationPolicyTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R28": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:DisaggregationOfRevenueTableTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2302301 - Disclosure - REVENUE (Tables)",
     "role": "http://www.grainger.com/role/RevenueTables",
     "shortName": "REVENUE (Tables)",
     "subGroupType": "tables",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:DisaggregationOfRevenueTableTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R29": {
     "firstAnchor": {
      "ancestors": [
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:PropertyPlantAndEquipmentTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2304301 - Disclosure - PROPERTY, BUILDINGS AND EQUIPMENT (Tables)",
     "role": "http://www.grainger.com/role/PropertyBuildingsAndEquipmentTables",
     "shortName": "PROPERTY, BUILDINGS AND EQUIPMENT (Tables)",
     "subGroupType": "tables",
     "uniqueAnchor": {
      "ancestors": [
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:PropertyPlantAndEquipmentTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R3": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:ProfitLoss",
      "reportCount": 1,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "statement",
     "isDefault": "false",
     "longName": "1003000 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE EARNINGS",
     "role": "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings",
     "shortName": "CONSOLIDATED STATEMENTS OF COMPREHENSIVE EARNINGS",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "-6",
      "lang": null,
      "name": "us-gaap:OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R30": {
     "firstAnchor": {
      "ancestors": [
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ScheduleOfGoodwillTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2307301 - Disclosure - GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)",
     "role": "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsTables",
     "shortName": "GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)",
     "subGroupType": "tables",
     "uniqueAnchor": {
      "ancestors": [
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ScheduleOfGoodwillTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R31": {
     "firstAnchor": {
      "ancestors": [
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ScheduleOfShortTermDebtTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2309301 - Disclosure - SHORT-TERM DEBT (Tables)",
     "role": "http://www.grainger.com/role/ShortTermDebtTables",
     "shortName": "SHORT-TERM DEBT (Tables)",
     "subGroupType": "tables",
     "uniqueAnchor": {
      "ancestors": [
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ScheduleOfShortTermDebtTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R32": {
     "firstAnchor": {
      "ancestors": [
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ScheduleOfDebtInstrumentsTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2311301 - Disclosure - LONG-TERM DEBT (Tables)",
     "role": "http://www.grainger.com/role/LongTermDebtTables",
     "shortName": "LONG-TERM DEBT (Tables)",
     "subGroupType": "tables",
     "uniqueAnchor": {
      "ancestors": [
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ScheduleOfDebtInstrumentsTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R33": {
     "firstAnchor": {
      "ancestors": [
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ScheduleOfNetBenefitCostsTableTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2312301 - Disclosure - EMPLOYEE BENEFITS (Tables)",
     "role": "http://www.grainger.com/role/EmployeeBenefitsTables",
     "shortName": "EMPLOYEE BENEFITS (Tables)",
     "subGroupType": "tables",
     "uniqueAnchor": {
      "ancestors": [
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ScheduleOfNetBenefitCostsTableTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R34": {
     "firstAnchor": {
      "ancestors": [
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "gww:AssetsAndLiabilitiesLesseeTableTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2313301 - Disclosure - LEASES (Tables)",
     "role": "http://www.grainger.com/role/LeasesTables",
     "shortName": "LEASES (Tables)",
     "subGroupType": "tables",
     "uniqueAnchor": {
      "ancestors": [
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "gww:AssetsAndLiabilitiesLesseeTableTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R35": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2315301 - Disclosure - STOCK INCENTIVE PLANS (Tables)",
     "role": "http://www.grainger.com/role/StockIncentivePlansTables",
     "shortName": "STOCK INCENTIVE PLANS (Tables)",
     "subGroupType": "tables",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R36": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ScheduleOfCapitalUnitsTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2316301 - Disclosure - CAPITAL STOCK (Tables)",
     "role": "http://www.grainger.com/role/CapitalStockTables",
     "shortName": "CAPITAL STOCK (Tables)",
     "subGroupType": "tables",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ScheduleOfCapitalUnitsTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R37": {
     "firstAnchor": {
      "ancestors": [
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2317301 - Disclosure - ACCUMULATED OTHER COMPREHENSIVE EARNINGS (LOSSES) (AOCE) (Tables)",
     "role": "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceTables",
     "shortName": "ACCUMULATED OTHER COMPREHENSIVE EARNINGS (LOSSES) (AOCE) (Tables)",
     "subGroupType": "tables",
     "uniqueAnchor": {
      "ancestors": [
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R38": {
     "firstAnchor": {
      "ancestors": [
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2318301 - Disclosure - INCOME TAXES (Tables)",
     "role": "http://www.grainger.com/role/IncomeTaxesTables",
     "shortName": "INCOME TAXES (Tables)",
     "subGroupType": "tables",
     "uniqueAnchor": {
      "ancestors": [
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R39": {
     "firstAnchor": {
      "ancestors": [
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ScheduleOfSegmentReportingInformationBySegmentTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2319301 - Disclosure - SEGMENT INFORMATION (Tables)",
     "role": "http://www.grainger.com/role/SegmentInformationTables",
     "shortName": "SEGMENT INFORMATION (Tables)",
     "subGroupType": "tables",
     "uniqueAnchor": {
      "ancestors": [
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ScheduleOfSegmentReportingInformationBySegmentTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R4": {
     "firstAnchor": null,
     "groupType": "statement",
     "isDefault": "false",
     "longName": "1003501 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE EARNINGS (Parentheticals)",
     "role": "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarningsParentheticals",
     "shortName": "CONSOLIDATED STATEMENTS OF COMPREHENSIVE EARNINGS (Parentheticals)",
     "subGroupType": "parenthetical",
     "uniqueAnchor": null
    },
    "R40": {
     "firstAnchor": {
      "ancestors": [
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ScheduleOfQuarterlyFinancialInformationTableTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2321301 - Disclosure - SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Tables)",
     "role": "http://www.grainger.com/role/SelectedQuarterlyFinancialDataUnauditedTables",
     "shortName": "SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Tables)",
     "subGroupType": "tables",
     "uniqueAnchor": {
      "ancestors": [
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:ScheduleOfQuarterlyFinancialInformationTableTextBlock",
      "reportCount": 1,
      "unique": true,
      "unitRef": null,
      "xsiNil": "false"
     }
    },
    "R41": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "us-gaap:RevenueRecognitionPolicyTextBlock",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "2",
      "first": true,
      "lang": null,
      "name": "gww:ServiceFeeRevenue",
      "reportCount": 1,
      "unitRef": "number",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2401402 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)",
     "role": "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails",
     "shortName": "SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "us-gaap:RevenueRecognitionPolicyTextBlock",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-6",
      "lang": null,
      "name": "us-gaap:ContractWithCustomerRefundLiability",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R42": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "INF",
      "first": true,
      "lang": null,
      "name": "gww:RevenueFromContractWithCustomerExcludingAssessedTaxPercentage",
      "reportCount": 1,
      "unique": true,
      "unitRef": "number",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2402402 - Disclosure - REVENUE (Details)",
     "role": "http://www.grainger.com/role/RevenueDetails",
     "shortName": "REVENUE (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "INF",
      "first": true,
      "lang": null,
      "name": "gww:RevenueFromContractWithCustomerExcludingAssessedTaxPercentage",
      "reportCount": 1,
      "unique": true,
      "unitRef": "number",
      "xsiNil": "false"
     }
    },
    "R43": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "ix:continuation",
       "us-gaap:PropertyPlantAndEquipmentTextBlock",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:PropertyPlantAndEquipmentGross",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2404402 - Disclosure - PROPERTY, BUILDINGS AND EQUIPMENT (Details)",
     "role": "http://www.grainger.com/role/PropertyBuildingsAndEquipmentDetails",
     "shortName": "PROPERTY, BUILDINGS AND EQUIPMENT (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "ix:continuation",
       "us-gaap:PropertyPlantAndEquipmentTextBlock",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:PropertyPlantAndEquipmentGross",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R44": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:AmortizationOfIntangibleAssets",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2407402 - Disclosure - GOODWILL AND OTHER INTANGIBLE ASSETS Additional Information (Details)",
     "role": "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsAdditionalInformationDetails",
     "shortName": "GOODWILL AND OTHER INTANGIBLE ASSETS Additional Information (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:AmortizationOfIntangibleAssets",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R45": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "us-gaap:ScheduleOfGoodwillTextBlock",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2018Q4",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:Goodwill",
      "reportCount": 1,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2407403 - Disclosure - GOODWILL AND OTHER INTANGIBLE ASSETS Balances and Changes in Carrying Amounts of Goodwill (Details)",
     "role": "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsBalancesAndChangesInCarryingAmountsOfGoodwillDetails",
     "shortName": "GOODWILL AND OTHER INTANGIBLE ASSETS Balances and Changes in Carrying Amounts of Goodwill (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "us-gaap:ScheduleOfGoodwillTextBlock",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2018Q4YTD",
      "decimals": "-6",
      "lang": null,
      "name": "us-gaap:GoodwillImpairmentLoss",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R46": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "us-gaap:ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:IntangibleAssetsGrossExcludingGoodwill",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2407404 - Disclosure - GOODWILL AND OTHER INTANGIBLE ASSETS Intangible assets included in Other assets and intangibles (Details)",
     "role": "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails",
     "shortName": "GOODWILL AND OTHER INTANGIBLE ASSETS Intangible assets included in Other assets and intangibles (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "us-gaap:ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:IntangibleAssetsGrossExcludingGoodwill",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R47": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2407405 - Disclosure - GOODWILL AND OTHER INTANGIBLE ASSETS Estimated amortization expense (Details)",
     "role": "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsEstimatedAmortizationExpenseDetails",
     "shortName": "GOODWILL AND OTHER INTANGIBLE ASSETS Estimated amortization expense (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R48": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2018Q4YTD_us-gaap_IncomeStatementLocationAxis_us-gaap_SellingGeneralAndAdministrativeExpensesMember",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:RestructuringCosts",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2408406 - Disclosure - RESTRUCTURING RESERVES RESTRUCTURING (Details)",
     "role": "http://www.grainger.com/role/RestructuringReservesRestructuringDetails",
     "shortName": "RESTRUCTURING RESERVES RESTRUCTURING (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2018Q4YTD_us-gaap_IncomeStatementLocationAxis_us-gaap_SellingGeneralAndAdministrativeExpensesMember",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:RestructuringCosts",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R49": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:ShortTermBorrowings",
      "reportCount": 1,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2409402 - Disclosure - SHORT-TERM DEBT (Details)",
     "role": "http://www.grainger.com/role/ShortTermDebtDetails",
     "shortName": "SHORT-TERM DEBT (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4_us-gaap_ShortTermDebtTypeAxis_us-gaap_LineOfCreditMember",
      "decimals": "-6",
      "lang": null,
      "name": "us-gaap:LinesOfCreditCurrent",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R5": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:CashAndCashEquivalentsAtCarryingValue",
      "reportCount": 1,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "statement",
     "isDefault": "false",
     "longName": "1004000 - Statement - CONSOLIDATED BALANCE SHEETS",
     "role": "http://www.grainger.com/role/ConsolidatedBalanceSheets",
     "shortName": "CONSOLIDATED BALANCE SHEETS",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-6",
      "lang": null,
      "name": "us-gaap:AccountsReceivableNetCurrent",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R50": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "us-gaap:ScheduleOfMaturitiesOfLongTermDebtTableTextBlock",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:DebtInstrumentCarryingAmount",
      "reportCount": 1,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2411402 - Disclosure - LONG-TERM DEBT - SCHEDULE OF LONG-TERM DEBT (Details)",
     "role": "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails",
     "shortName": "LONG-TERM DEBT - SCHEDULE OF LONG-TERM DEBT (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "us-gaap:ScheduleOfDebtInstrumentsTextBlock",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-6",
      "lang": null,
      "name": "gww:LongTermDebtGrossFairValueDisclosure",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R51": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2017Q4",
      "decimals": "-8",
      "first": true,
      "lang": null,
      "name": "us-gaap:DebtInstrumentRepurchaseAmount",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2411403 - Disclosure - LONG-TERM DEBT (Details)",
     "role": "http://www.grainger.com/role/LongTermDebtDetails",
     "shortName": "LONG-TERM DEBT (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2017Q4",
      "decimals": "-8",
      "first": true,
      "lang": null,
      "name": "us-gaap:DebtInstrumentRepurchaseAmount",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R52": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:LongTermDebtCurrent",
      "reportCount": 1,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2411404 - Disclosure - LONG-TERM DEBT - SCHEDULED AGGREGATE PRINCIPAL PAYMENTS (Details)",
     "role": "http://www.grainger.com/role/LongTermDebtScheduledAggregatePrincipalPaymentsDetails",
     "shortName": "LONG-TERM DEBT - SCHEDULED AGGREGATE PRINCIPAL PAYMENTS (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "us-gaap:ScheduleOfMaturitiesOfLongTermDebtTableTextBlock",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-6",
      "lang": null,
      "name": "us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R53": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "INF",
      "first": true,
      "lang": null,
      "name": "gww:ProfitSharingAutomaticContributionByEmployerPercentage",
      "reportCount": 1,
      "unitRef": "number",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2412402 - Disclosure - EMPLOYEE BENEFITS - Defined Contribution Plans (Details)",
     "role": "http://www.grainger.com/role/EmployeeBenefitsDefinedContributionPlansDetails",
     "shortName": "EMPLOYEE BENEFITS - Defined Contribution Plans (Details)",
     "subGroupType": "details",
     "uniqueAnchor": null
    },
    "R54": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "INF",
      "first": true,
      "lang": null,
      "name": "gww:ProfitSharingAutomaticContributionByEmployerPercentage",
      "reportCount": 1,
      "unitRef": "number",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2412403 - Disclosure - EMPLOYEE BENEFITS - Postretirement Benefits (Details)",
     "role": "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails",
     "shortName": "EMPLOYEE BENEFITS - Postretirement Benefits (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "D2017Q3August31",
      "decimals": "-6",
      "lang": null,
      "name": "us-gaap:OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R55": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "gww:AssetsAndLiabilitiesLesseeTableTextBlock",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:OperatingLeaseRightOfUseAsset",
      "reportCount": 1,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2413403 - Disclosure - LEASES - Schedule of Operating Lease Information (Details)",
     "role": "http://www.grainger.com/role/LeasesScheduleOfOperatingLeaseInformationDetails",
     "shortName": "LEASES - Schedule of Operating Lease Information (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "gww:AssetsAndLiabilitiesLesseeTableTextBlock",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-6",
      "lang": null,
      "name": "us-gaap:OperatingLeaseLiabilityCurrent",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R56": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "us-gaap:LeaseCostTableTextBlock",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": null,
      "first": true,
      "lang": "en-US",
      "name": "us-gaap:OperatingLeaseWeightedAverageRemainingLeaseTerm1",
      "reportCount": 1,
      "unitRef": null,
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2413404 - Disclosure - LEASES - Schedule of Maturities of Operating Leases (Details)",
     "role": "http://www.grainger.com/role/LeasesScheduleOfMaturitiesOfOperatingLeasesDetails",
     "shortName": "LEASES - Schedule of Maturities of Operating Leases (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "us-gaap:LesseeOperatingLeaseLiabilityMaturityTableTextBlock",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-6",
      "lang": null,
      "name": "us-gaap:LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R57": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-5",
      "first": true,
      "lang": null,
      "name": "us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant",
      "reportCount": 1,
      "unique": true,
      "unitRef": "shares",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2415402 - Disclosure - STOCK INCENTIVE PLANS (Details)",
     "role": "http://www.grainger.com/role/StockIncentivePlansDetails",
     "shortName": "STOCK INCENTIVE PLANS (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-5",
      "first": true,
      "lang": null,
      "name": "us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant",
      "reportCount": 1,
      "unique": true,
      "unitRef": "shares",
      "xsiNil": "false"
     }
    },
    "R58": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:StockOptionPlanExpense",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2415403 - Disclosure - STOCK INCENTIVE PLANS - Stock Options Outstanding and Exercisable (Details)",
     "role": "http://www.grainger.com/role/StockIncentivePlansStockOptionsOutstandingAndExercisableDetails",
     "shortName": "STOCK INCENTIVE PLANS - Stock Options Outstanding and Exercisable (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:StockOptionPlanExpense",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R59": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:RestrictedStockExpense",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2415405 - Disclosure - STOCK INCENTIVE PLANS - Restricted Stock Units (Details)",
     "role": "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails",
     "shortName": "STOCK INCENTIVE PLANS - Restricted Stock Units (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:RestrictedStockExpense",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R6": {
     "firstAnchor": null,
     "groupType": "statement",
     "isDefault": "false",
     "longName": "1004501 - Statement - CONSOLIDATED BALANCE SHEETS (Parentheticals)",
     "role": "http://www.grainger.com/role/ConsolidatedBalanceSheetsParentheticals",
     "shortName": "CONSOLIDATED BALANCE SHEETS (Parentheticals)",
     "subGroupType": "parenthetical",
     "uniqueAnchor": null
    },
    "R60": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2018Q4_us-gaap_StatementEquityComponentsAxis_us-gaap_CommonStockMember",
      "decimals": "INF",
      "first": true,
      "lang": null,
      "name": "us-gaap:CommonStockSharesOutstanding",
      "reportCount": 1,
      "unitRef": "shares",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2416402 - Disclosure - CAPITAL STOCK (Details)",
     "role": "http://www.grainger.com/role/CapitalStockDetails",
     "shortName": "CAPITAL STOCK (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2016Q4_us-gaap_StatementEquityComponentsAxis_us-gaap_CommonStockMember",
      "decimals": "INF",
      "lang": null,
      "name": "us-gaap:CommonStockSharesOutstanding",
      "reportCount": 1,
      "unique": true,
      "unitRef": "shares",
      "xsiNil": "false"
     }
    },
    "R61": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2018Q4",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest",
      "reportCount": 1,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2417402 - Disclosure - ACCUMULATED OTHER COMPREHENSIVE EARNINGS (LOSSES) (AOCE) (Details)",
     "role": "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails",
     "shortName": "ACCUMULATED OTHER COMPREHENSIVE EARNINGS (LOSSES) (AOCE) (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "ix:continuation",
       "us-gaap:ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2016Q4_us-gaap_StatementEquityComponentsAxis_us-gaap_AccumulatedForeignCurrencyAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember",
      "decimals": "-6",
      "lang": null,
      "name": "us-gaap:StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R62": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "us-gaap:ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2418402 - Disclosure - INCOME TAXES - Net Earnings Before Income Taxes by Geographical Area (Details)",
     "role": "http://www.grainger.com/role/IncomeTaxesNetEarningsBeforeIncomeTaxesByGeographicalAreaDetails",
     "shortName": "INCOME TAXES - Net Earnings Before Income Taxes by Geographical Area (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "us-gaap:ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R63": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "us-gaap:ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:CurrentFederalTaxExpenseBenefit",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2418403 - Disclosure - INCOME TAXES (Details)",
     "role": "http://www.grainger.com/role/IncomeTaxesDetails",
     "shortName": "INCOME TAXES (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "us-gaap:ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:CurrentFederalTaxExpenseBenefit",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R64": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:OperatingLossCarryforwards",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2418404 - Disclosure - INCOME TAXES - Income Tax Effects of Temporary Differences (Details)",
     "role": "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails",
     "shortName": "INCOME TAXES - Income Tax Effects of Temporary Differences (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:OperatingLossCarryforwards",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R65": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2018Q4",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:DeferredTaxAssetsValuationAllowance",
      "reportCount": 1,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2418405 - Disclosure - INCOME TAXES - Changes in Valuation Allowance (Details)",
     "role": "http://www.grainger.com/role/IncomeTaxesChangesInValuationAllowanceDetails",
     "shortName": "INCOME TAXES - Changes in Valuation Allowance (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD_us-gaap_ValuationAllowanceByDeferredTaxAssetAxis_gww_ValuationAllowanceIncreaseRelatedtoForeignNetOperatingLossCarryforwardsMember",
      "decimals": "-6",
      "lang": null,
      "name": "us-gaap:ValuationAllowanceDeferredTaxAssetChangeInAmount",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R66": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "us-gaap:ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2418406 - Disclosure - INCOME TAXES - Reconciliation of Income Tax Expense with Federal Income Taxes at the Statutory Rate (Details)",
     "role": "http://www.grainger.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseWithFederalIncomeTaxesAtStatutoryRateDetails",
     "shortName": "INCOME TAXES - Reconciliation of Income Tax Expense with Federal Income Taxes at the Statutory Rate (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "us-gaap:ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R67": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "gww:TaxPositionsWithUncertainTimingOfDeductibility",
      "reportCount": 1,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2418407 - Disclosure - INCOME TAXES - Changes in Liability for Tax Uncertainties, Excluding Interest (Details)",
     "role": "http://www.grainger.com/role/IncomeTaxesChangesInLiabilityForTaxUncertaintiesExcludingInterestDetails",
     "shortName": "INCOME TAXES - Changes in Liability for Tax Uncertainties, Excluding Interest (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2016Q4",
      "decimals": "-6",
      "lang": null,
      "name": "us-gaap:UnrecognizedTaxBenefits",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R68": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "gww:AssetsAndLiabilitiesLesseeTableTextBlock",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2019Q4",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:OperatingLeaseRightOfUseAsset",
      "reportCount": 1,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2419402 - Disclosure - SEGMENT INFORMATION (Details)",
     "role": "http://www.grainger.com/role/SegmentInformationDetails",
     "shortName": "SEGMENT INFORMATION (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "INF",
      "lang": null,
      "name": "us-gaap:NumberOfReportableSegments",
      "reportCount": 1,
      "unique": true,
      "unitRef": "segment",
      "xsiNil": "false"
     }
    },
    "R69": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "ix:continuation",
       "us-gaap:ScheduleOfQuarterlyFinancialInformationTableTextBlock",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4QTD",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax",
      "reportCount": 1,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2421402 - Disclosure - SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Details)",
     "role": "http://www.grainger.com/role/SelectedQuarterlyFinancialDataUnauditedDetails",
     "shortName": "SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "ix:continuation",
       "us-gaap:ScheduleOfQuarterlyFinancialInformationTableTextBlock",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4QTD",
      "decimals": "-6",
      "lang": null,
      "name": "us-gaap:CostOfGoodsAndServicesSold",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R7": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:ProfitLoss",
      "reportCount": 1,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "statement",
     "isDefault": "false",
     "longName": "1005000 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS",
     "role": "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows",
     "shortName": "CONSOLIDATED STATEMENTS OF CASH FLOWS",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FD2019Q4YTD",
      "decimals": "-6",
      "lang": null,
      "name": "us-gaap:ProvisionForDoubtfulAccounts",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R70": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "I2015Q3Aug31_us-gaap_CreditFacilityAxis_us-gaap_RevolvingCreditFacilityMember_us-gaap_LongtermDebtTypeAxis_us-gaap_LineOfCreditMember",
      "decimals": "INF",
      "first": true,
      "lang": null,
      "name": "us-gaap:LineOfCreditFacilityMaximumBorrowingCapacity",
      "reportCount": 1,
      "unitRef": "gbp",
      "xsiNil": "false"
     },
     "groupType": "disclosure",
     "isDefault": "false",
     "longName": "2422401 - Disclosure - SUBSEQUENT EVENT (Details)",
     "role": "http://www.grainger.com/role/SubsequentEventDetails",
     "shortName": "SUBSEQUENT EVENT (Details)",
     "subGroupType": "details",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "I2020Q1FEB29_us-gaap_CreditFacilityAxis_us-gaap_RevolvingCreditFacilityMember_us-gaap_LongtermDebtTypeAxis_us-gaap_LineOfCreditMember_us-gaap_SubsequentEventTypeAxis_us-gaap_SubsequentEventMember",
      "decimals": "INF",
      "lang": null,
      "name": "us-gaap:LineOfCreditFacilityMaximumBorrowingCapacity",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R8": {
     "firstAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2016Q4",
      "decimals": "-6",
      "first": true,
      "lang": null,
      "name": "us-gaap:StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest",
      "reportCount": 1,
      "unitRef": "usd",
      "xsiNil": "false"
     },
     "groupType": "statement",
     "isDefault": "false",
     "longName": "1006000 - Statement - CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY",
     "role": "http://www.grainger.com/role/ConsolidatedStatementsOfShareholdersEquity",
     "shortName": "CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY",
     "subGroupType": "",
     "uniqueAnchor": {
      "ancestors": [
       "span",
       "span",
       "div",
       "td",
       "tr",
       "table",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "baseRef": "gww20191231-10k.htm",
      "contextRef": "FI2016Q4_us-gaap_StatementEquityComponentsAxis_us-gaap_CommonStockMember",
      "decimals": "-6",
      "lang": null,
      "name": "us-gaap:StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest",
      "reportCount": 1,
      "unique": true,
      "unitRef": "usd",
      "xsiNil": "false"
     }
    },
    "R9": {
     "firstAnchor": null,
     "groupType": "statement",
     "isDefault": "false",
     "longName": "1006501 - Statement - CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parentheticals)",
     "role": "http://www.grainger.com/role/ConsolidatedStatementsOfShareholdersEquityParentheticals",
     "shortName": "CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parentheticals)",
     "subGroupType": "parenthetical",
     "uniqueAnchor": null
    }
   },
   "segmentCount": 87,
   "tag": {
    "country_CA": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "CANADA",
        "terseLabel": "Canada"
       }
      }
     },
     "localname": "CA",
     "nsuri": "http://xbrl.sec.gov/country/2017-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsAdditionalInformationDetails",
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsBalancesAndChangesInCarryingAmountsOfGoodwillDetails",
      "http://www.grainger.com/role/RevenueDetails",
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "country_US": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "UNITED STATES",
        "terseLabel": "United States"
       }
      }
     },
     "localname": "US",
     "nsuri": "http://xbrl.sec.gov/country/2017-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsBalancesAndChangesInCarryingAmountsOfGoodwillDetails",
      "http://www.grainger.com/role/RevenueDetails",
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "dei_AmendmentFlag": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Boolean flag that is true when the XBRL content amends previously-filed or accepted submission.",
        "label": "Amendment Flag",
        "terseLabel": "Amendment Flag"
       }
      }
     },
     "localname": "AmendmentFlag",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "booleanItemType"
    },
    "dei_CityAreaCode": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Area code of city",
        "label": "City Area Code",
        "terseLabel": "City Area Code"
       }
      }
     },
     "localname": "CityAreaCode",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "normalizedStringItemType"
    },
    "dei_CoverAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Cover page.",
        "label": "Cover page."
       }
      }
     },
     "localname": "CoverAbstract",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "xbrltype": "stringItemType"
    },
    "dei_CurrentFiscalYearEndDate": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "End date of current fiscal year in the format --MM-DD.",
        "label": "Current Fiscal Year End Date",
        "terseLabel": "Current Fiscal Year End Date"
       }
      }
     },
     "localname": "CurrentFiscalYearEndDate",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "gMonthDayItemType"
    },
    "dei_DocumentAnnualReport": {
     "auth_ref": [
      "r475"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Boolean flag that is true only for a form used as an annual report.",
        "label": "Document Annual Report",
        "terseLabel": "Document Annual Report"
       }
      }
     },
     "localname": "DocumentAnnualReport",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "booleanItemType"
    },
    "dei_DocumentFiscalPeriodFocus": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Fiscal period values are FY, Q1, Q2, and Q3.  1st, 2nd and 3rd quarter 10-Q or 10-QT statements have value Q1, Q2, and Q3 respectively, with 10-K, 10-KT or other fiscal year statements having FY.",
        "label": "Document Fiscal Period Focus",
        "terseLabel": "Document Fiscal Period Focus"
       }
      }
     },
     "localname": "DocumentFiscalPeriodFocus",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "fiscalPeriodItemType"
    },
    "dei_DocumentFiscalYearFocus": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "This is focus fiscal year of the document report in CCYY format. For a 2006 annual report, which may also provide financial information from prior periods, fiscal 2006 should be given as the fiscal year focus. Example: 2006.",
        "label": "Document Fiscal Year Focus",
        "terseLabel": "Document Fiscal Year Focus"
       }
      }
     },
     "localname": "DocumentFiscalYearFocus",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "gYearItemType"
    },
    "dei_DocumentPeriodEndDate": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The end date of the period reflected on the cover page if a periodic report. For all other reports and registration statements containing historical data, it is the date up through which that historical data is presented.  If there is no historical data in the report, use the filing date. The format of the date is CCYY-MM-DD.",
        "label": "Document Period End Date",
        "terseLabel": "Document Period End Date"
       }
      }
     },
     "localname": "DocumentPeriodEndDate",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "dateItemType"
    },
    "dei_DocumentTransitionReport": {
     "auth_ref": [
      "r474"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Boolean flag that is true only for a form used as a transition report.",
        "label": "Document Transition Report",
        "terseLabel": "Document Transition Report"
       }
      }
     },
     "localname": "DocumentTransitionReport",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "booleanItemType"
    },
    "dei_DocumentType": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.",
        "label": "Document Type",
        "terseLabel": "Document Type"
       }
      }
     },
     "localname": "DocumentType",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "submissionTypeItemType"
    },
    "dei_DocumentsIncorporatedByReferenceTextBlock": {
     "auth_ref": [
      "r472"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Documents incorporated by reference.",
        "label": "Documents Incorporated by Reference [Text Block]",
        "terseLabel": "Documents Incorporated by Reference"
       }
      }
     },
     "localname": "DocumentsIncorporatedByReferenceTextBlock",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "textBlockItemType"
    },
    "dei_EntityAddressAddressLine1": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Address Line 1 such as Attn, Building Name, Street Name",
        "label": "Entity Address, Address Line One",
        "terseLabel": "Entity Address, Address Line One"
       }
      }
     },
     "localname": "EntityAddressAddressLine1",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "normalizedStringItemType"
    },
    "dei_EntityAddressCityOrTown": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Name of the City or Town",
        "label": "Entity Address, City or Town",
        "terseLabel": "Entity Address, City or Town"
       }
      }
     },
     "localname": "EntityAddressCityOrTown",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "normalizedStringItemType"
    },
    "dei_EntityAddressPostalZipCode": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Code for the postal or zip code",
        "label": "Entity Address, Postal Zip Code",
        "terseLabel": "Entity Address, Postal Zip Code"
       }
      }
     },
     "localname": "EntityAddressPostalZipCode",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "normalizedStringItemType"
    },
    "dei_EntityAddressStateOrProvince": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Name of the state or province.",
        "label": "Entity Address, State or Province",
        "terseLabel": "Entity Address, State or Province"
       }
      }
     },
     "localname": "EntityAddressStateOrProvince",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "stateOrProvinceItemType"
    },
    "dei_EntityCentralIndexKey": {
     "auth_ref": [
      "r476"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.",
        "label": "Entity Central Index Key",
        "terseLabel": "Entity Central Index Key"
       }
      }
     },
     "localname": "EntityCentralIndexKey",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "centralIndexKeyItemType"
    },
    "dei_EntityCommonStockSharesOutstanding": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Indicate number of shares or other units outstanding of each of registrant's classes of capital or common stock or other ownership interests, if and as stated on cover of related periodic report. Where multiple classes or units exist define each class/interest by adding class of stock items such as Common Class A [Member], Common Class B [Member] or Partnership Interest [Member] onto the Instrument [Domain] of the Entity Listings, Instrument.",
        "label": "Entity Common Stock, Shares Outstanding",
        "terseLabel": "Entity Common Stock, Shares Outstanding"
       }
      }
     },
     "localname": "EntityCommonStockSharesOutstanding",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "sharesItemType"
    },
    "dei_EntityCurrentReportingStatus": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Indicate 'Yes' or 'No' whether registrants (1) have filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that registrants were required to file such reports), and (2) have been subject to such filing requirements for the past 90 days. This information should be based on the registrant's current or most recent filing containing the related disclosure.",
        "label": "Entity Current Reporting Status",
        "terseLabel": "Entity Current Reporting Status"
       }
      }
     },
     "localname": "EntityCurrentReportingStatus",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "yesNoItemType"
    },
    "dei_EntityEmergingGrowthCompany": {
     "auth_ref": [
      "r476"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Indicate if registrant meets the emerging growth company criteria.",
        "label": "Entity Emerging Growth Company",
        "terseLabel": "Entity Emerging Growth Company"
       }
      }
     },
     "localname": "EntityEmergingGrowthCompany",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "booleanItemType"
    },
    "dei_EntityFileNumber": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.",
        "label": "Entity File Number",
        "terseLabel": "Entity File Number"
       }
      }
     },
     "localname": "EntityFileNumber",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "fileNumberItemType"
    },
    "dei_EntityFilerCategory": {
     "auth_ref": [
      "r476"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Indicate whether the registrant is one of the following: Large Accelerated Filer, Accelerated Filer, Non-accelerated Filer. Definitions of these categories are stated in Rule 12b-2 of the Exchange Act. This information should be based on the registrant's current or most recent filing containing the related disclosure.",
        "label": "Entity Filer Category",
        "terseLabel": "Entity Filer Category"
       }
      }
     },
     "localname": "EntityFilerCategory",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "filerCategoryItemType"
    },
    "dei_EntityIncorporationStateCountryCode": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Two-character EDGAR code representing the state or country of incorporation.",
        "label": "Entity Incorporation, State or Country Code",
        "terseLabel": "Entity Incorporation, State or Country Code"
       }
      }
     },
     "localname": "EntityIncorporationStateCountryCode",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "edgarStateCountryItemType"
    },
    "dei_EntityInteractiveDataCurrent": {
     "auth_ref": [
      "r477"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Boolean flag that is true when the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).",
        "label": "Entity Interactive Data Current",
        "terseLabel": "Entity Interactive Data Current"
       }
      }
     },
     "localname": "EntityInteractiveDataCurrent",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "yesNoItemType"
    },
    "dei_EntityPublicFloat": {
     "auth_ref": [],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The aggregate market value of the voting and non-voting common equity held by non-affiliates computed by reference to the price at which the common equity was last sold, or the average bid and asked price of such common equity, as of the last business day of the registrant's most recently completed second fiscal quarter.",
        "label": "Entity Public Float",
        "terseLabel": "Entity Public Float"
       }
      }
     },
     "localname": "EntityPublicFloat",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "monetaryItemType"
    },
    "dei_EntityRegistrantName": {
     "auth_ref": [
      "r476"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.",
        "label": "Entity Registrant Name",
        "terseLabel": "Entity Registrant Name"
       }
      }
     },
     "localname": "EntityRegistrantName",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "normalizedStringItemType"
    },
    "dei_EntityShellCompany": {
     "auth_ref": [
      "r476"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Boolean flag that is true when the registrant is a shell company as defined in Rule 12b-2 of the Exchange Act.",
        "label": "Entity Shell Company",
        "terseLabel": "Entity Shell Company"
       }
      }
     },
     "localname": "EntityShellCompany",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "booleanItemType"
    },
    "dei_EntitySmallBusiness": {
     "auth_ref": [
      "r476"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Indicates that the company is a Smaller Reporting Company (SRC).",
        "label": "Entity Small Business",
        "terseLabel": "Entity Small Business"
       }
      }
     },
     "localname": "EntitySmallBusiness",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "booleanItemType"
    },
    "dei_EntityTaxIdentificationNumber": {
     "auth_ref": [
      "r476"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.",
        "label": "Entity Tax Identification Number",
        "terseLabel": "Entity Tax Identification Number"
       }
      }
     },
     "localname": "EntityTaxIdentificationNumber",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "employerIdItemType"
    },
    "dei_EntityVoluntaryFilers": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Indicate 'Yes' or 'No' if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.",
        "label": "Entity Voluntary Filers",
        "terseLabel": "Entity Voluntary Filers"
       }
      }
     },
     "localname": "EntityVoluntaryFilers",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "yesNoItemType"
    },
    "dei_EntityWellKnownSeasonedIssuer": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Indicate 'Yes' or 'No' if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Is used on Form Type: 10-K, 10-Q, 8-K, 20-F, 6-K, 10-K/A, 10-Q/A, 20-F/A, 6-K/A, N-CSR, N-Q, N-1A.",
        "label": "Entity Well-known Seasoned Issuer",
        "terseLabel": "Entity Well-known Seasoned Issuer"
       }
      }
     },
     "localname": "EntityWellKnownSeasonedIssuer",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "yesNoItemType"
    },
    "dei_LocalPhoneNumber": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Local phone number for entity.",
        "label": "Local Phone Number",
        "terseLabel": "Local Phone Number"
       }
      }
     },
     "localname": "LocalPhoneNumber",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "normalizedStringItemType"
    },
    "dei_Security12bTitle": {
     "auth_ref": [
      "r471"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Title of a 12(b) registered security.",
        "label": "Title of 12(b) Security",
        "terseLabel": "Title of 12(b) Security"
       }
      }
     },
     "localname": "Security12bTitle",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "securityTitleItemType"
    },
    "dei_SecurityExchangeName": {
     "auth_ref": [
      "r473"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Name of the Exchange on which a security is registered.",
        "label": "Security Exchange Name",
        "terseLabel": "Security Exchange Name"
       }
      }
     },
     "localname": "SecurityExchangeName",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "edgarExchangeCodeItemType"
    },
    "dei_TradingSymbol": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Trading symbol of an instrument as listed on an exchange.",
        "label": "Trading Symbol",
        "terseLabel": "Trading Symbol"
       }
      }
     },
     "localname": "TradingSymbol",
     "nsuri": "http://xbrl.sec.gov/dei/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Cover"
     ],
     "xbrltype": "tradingSymbolItemType"
    },
    "gww_A5YearUnsecuredRevolvingLineOfCreditMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "5-Year Unsecured Revolving Line Of Credit [Member]",
        "label": "5-Year Unsecured Revolving Line Of Credit [Member]",
        "terseLabel": "5-Year Unsecured Revolving Line Of Credit [Member]"
       }
      }
     },
     "localname": "A5YearUnsecuredRevolvingLineOfCreditMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/ShortTermDebtDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_AccruedSalesIncentives": {
     "auth_ref": [],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Accrued Sales Incentives",
        "label": "Accrued Sales Incentives",
        "terseLabel": "Accrued sales incentives"
       }
      }
     },
     "localname": "AccruedSalesIncentives",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "gww_Amortizationperiodofcapitalizedsoftware": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amortization period of capitalized software",
        "label": "Amortization period of capitalized software",
        "terseLabel": "Capitalized software amortization period"
       }
      }
     },
     "localname": "Amortizationperiodofcapitalizedsoftware",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "durationItemType"
    },
    "gww_AssetsAndLiabilitiesLesseeTableTextBlock": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Assets And Liabilities, Lessee [Table Text Block]",
        "label": "Assets And Liabilities, Lessee [Table Text Block]",
        "terseLabel": "Schedule of Assets and Liabilities"
       }
      }
     },
     "localname": "AssetsAndLiabilitiesLesseeTableTextBlock",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/LeasesTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "gww_August2016CreditAgreementMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "August 2016 Credit Agreement [Member]",
        "label": "August 2016 Credit Agreement [Member]",
        "terseLabel": "August 2016 Credit Agreement [Member]"
       }
      }
     },
     "localname": "August2016CreditAgreementMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_BritishPoundDenominatedTermLoanMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "British Pound Denominated Term Loan [Member]",
        "label": "British Pound Denominated Term Loan [Member]",
        "terseLabel": "British pound term loan [Member]"
       }
      }
     },
     "localname": "BritishPoundDenominatedTermLoanMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_BuildingsStructuresandImprovementsEstimatedUsefulLife": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Buildings, Structures and Improvements, Estimated Useful Life",
        "label": "Buildings, Structures and Improvements, Estimated Useful Life",
        "terseLabel": "Buildings, structures and improvements, estimated useful life"
       }
      }
     },
     "localname": "BuildingsStructuresandImprovementsEstimatedUsefulLife",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "durationItemType"
    },
    "gww_CanadianDollarOfferedRateCDORMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Canadian Dollar Offered Rate (CDOR) [Member]",
        "label": "Canadian Dollar Offered Rate (CDOR) [Member]",
        "terseLabel": "Canadian Dollar Offered Rate (CDOR) [Member]"
       }
      }
     },
     "localname": "CanadianDollarOfferedRateCDORMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_CanadianDollarRevolvingCreditFacilityMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Canadian Dollar Revolving Credit Facility [Member]",
        "label": "Canadian Dollar Revolving Credit Facility [Member]",
        "terseLabel": "Canadian dollar revolving credit facility [Member]"
       }
      }
     },
     "localname": "CanadianDollarRevolvingCreditFacilityMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_CapitalStockAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "CAPITAL STOCK [Abstract]",
        "label": "CAPITAL STOCK [Abstract]"
       }
      }
     },
     "localname": "CapitalStockAbstract",
     "nsuri": "http://www.grainger.com/20191231",
     "xbrltype": "stringItemType"
    },
    "gww_CapitalStockTextBlock": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of the activity of outstanding common stock and common stock held in treasury.",
        "label": "Capital Stock [Text Block]",
        "terseLabel": "CAPITAL STOCK"
       }
      }
     },
     "localname": "CapitalStockTextBlock",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/CapitalStock"
     ],
     "xbrltype": "textBlockItemType"
    },
    "gww_CashClassification": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Original Maturity in days for cash.",
        "label": "Cash Classification",
        "terseLabel": "Original maturity of cash (days)"
       }
      }
     },
     "localname": "CashClassification",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "durationItemType"
    },
    "gww_CommercialMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Commercial [Member]",
        "label": "Commercial [Member]",
        "terseLabel": "Commercial [Member]"
       }
      }
     },
     "localname": "CommercialMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_ContingenciesAndLegalMattersAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "CONTINGENCIES AND LEGAL MATTERS [Abstract]",
        "label": "CONTINGENCIES AND LEGAL MATTERS [Abstract]"
       }
      }
     },
     "localname": "ContingenciesAndLegalMattersAbstract",
     "nsuri": "http://www.grainger.com/20191231",
     "xbrltype": "stringItemType"
    },
    "gww_ContractorsMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Contractors [Member]",
        "label": "Contractors [Member]",
        "terseLabel": "Contractors [Member]"
       }
      }
     },
     "localname": "ContractorsMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_DebtInstrumentNumberOfTermExtensions": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Debt Instrument, Number Of Term Extensions",
        "label": "Debt Instrument, Number Of Term Extensions",
        "terseLabel": "Number of term extensions"
       }
      }
     },
     "localname": "DebtInstrumentNumberOfTermExtensions",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/SubsequentEventDetails"
     ],
     "xbrltype": "integerItemType"
    },
    "gww_DebtInstrumentTermExtension": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Debt Instrument, Term Extension",
        "label": "Debt Instrument, Term Extension",
        "terseLabel": "Term extension"
       }
      }
     },
     "localname": "DebtInstrumentTermExtension",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/SubsequentEventDetails"
     ],
     "xbrltype": "durationItemType"
    },
    "gww_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNetFairValue": {
     "auth_ref": [],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Debt Instrument, Unamortized, Discount (Premium) And Debt Issuance Costs, Net, Fair Value",
        "label": "Debt Instrument, Unamortized, Discount (Premium) And Debt Issuance Costs, Net, Fair Value",
        "negatedTerseLabel": "Debt Instrument, Unamortized, Discount (Premium) And Debt Issuance Costs, Net, Fair Value"
       }
      }
     },
     "localname": "DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNetFairValue",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "gww_DeferredTaxAssetValuationAllowanceRollForward": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Deferred Tax Asset, Valuation Allowance [Roll Forward]",
        "label": "Deferred Tax Asset, Valuation Allowance [Roll Forward]",
        "terseLabel": "Deferred Tax Asset, Valuation Allowance [Roll Forward]"
       }
      }
     },
     "localname": "DeferredTaxAssetValuationAllowanceRollForward",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesChangesInValuationAllowanceDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "gww_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeDeferredTaxes": {
     "auth_ref": [],
     "calculation": {
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails": {
       "order": 3.0,
       "parentTag": "us-gaap_AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax",
       "weight": -1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tax effects of the net changes to accumulated comprehensive income during the period related to benefit plans.",
        "label": "Defined Benefit Plan Accumulated Other Comprehensive Income Deferred Taxes",
        "terseLabel": "Deferred tax (liability)"
       }
      }
     },
     "localname": "DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeDeferredTaxes",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "gww_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationCatastrophicDrugBenefit": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Catastrophic Drug Benefit",
        "label": "Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Catastrophic Drug Benefit",
        "terseLabel": "Catastrophic drug benefit"
       }
      }
     },
     "localname": "DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationCatastrophicDrugBenefit",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "gww_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationExpectedLongTermReturnOnAssets": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "An assumption as to the rate of return on plan assets reflecting the average rate of earnings expected on the funds invested or to be invested to provide for the benefits included in the benefit obligation.",
        "label": "Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Expected Long Term Return On Assets",
        "terseLabel": "Expected long-term rate of return on plan assets, net of tax"
       }
      }
     },
     "localname": "DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationExpectedLongTermReturnOnAssets",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "gww_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationHRACreditInflationIndexForGranfatheredRetirees": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, HRA Credit Inflation Index For Granfathered Retirees",
        "label": "Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, HRA Credit Inflation Index For Granfathered Retirees",
        "terseLabel": "HRA credit inflation index for grandfathered retirees"
       }
      }
     },
     "localname": "DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationHRACreditInflationIndexForGranfatheredRetirees",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "gww_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationHealthCareCostTrendRateAssumedForNextFiscalYearPostAge65": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Health Care Cost Trend Rate Assumed For Next Fiscal Year, Post Age 65",
        "label": "Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Health Care Cost Trend Rate Assumed For Next Fiscal Year, Post Age 65",
        "terseLabel": "Post age 65"
       }
      }
     },
     "localname": "DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationHealthCareCostTrendRateAssumedForNextFiscalYearPostAge65",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "gww_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationHealthCareCostTrendRateAssumedForNextFiscalYearPreAge65": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The assumed health care cost trend rate for the next year used to determine benefit obligations. This is based upon the annual rate of change in the cost of health care benefits currently provided by the postretirement benefit plan, due to factors other than changes in the composition of the plan population by age and dependency status.",
        "label": "Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Health Care Cost Trend Rate Assumed For Next Fiscal Year, Pre Age 65",
        "terseLabel": "Pre age 65"
       }
      }
     },
     "localname": "DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationHealthCareCostTrendRateAssumedForNextFiscalYearPreAge65",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "gww_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationUltimateHealthCareCostTrendRate": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The ultimate trend rate for health care costs used to determine benefit obligations.",
        "label": "Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Ultimate Health Care Cost Trend Rate",
        "terseLabel": "Ultimate healthcare cost trend rate"
       }
      }
     },
     "localname": "DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationUltimateHealthCareCostTrendRate",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "gww_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationYearThatRateReachesUltimateTrendRate": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The year when the ultimate health care cost trend rate is expected to be reached, which is used to determine benefit obligations.",
        "label": "Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Year That Rate Reaches Ultimate Trend Rate",
        "terseLabel": "Year ultimate healthcare cost trend rate reached"
       }
      }
     },
     "localname": "DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationYearThatRateReachesUltimateTrendRate",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "gww_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostHRACreditInflationIndexforGrandfatheredRetirees": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost HRA Credit INflation INdex for Grandfathered Retirees",
        "label": "Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost HRA Credit Inflation Index for Grandfathered Retirees",
        "terseLabel": "HRA credit inflation index for grandfathered retirees"
       }
      }
     },
     "localname": "DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostHRACreditInflationIndexforGrandfatheredRetirees",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "gww_DefinedBenefitPlanExpectedFutureBenefitPaymentTotal": {
     "auth_ref": [],
     "calculation": {
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Defined Benefit Plan, Expected Future Benefit Payment, Total",
        "label": "Defined Benefit Plan, Expected Future Benefit Payment, Total",
        "totalLabel": "Total"
       }
      }
     },
     "localname": "DefinedBenefitPlanExpectedFutureBenefitPaymentTotal",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "gww_DefinedBenefitPlanFairValueofPlanLiabilities": {
     "auth_ref": [],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Defined Benefit Plan, Fair Value of Plan Liabilities",
        "label": "Defined Benefit Plan, Fair Value of Plan Liabilities",
        "negatedTerseLabel": "Less: trust liabilities"
       }
      }
     },
     "localname": "DefinedBenefitPlanFairValueofPlanLiabilities",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "gww_DefinedBenefitPlanHealthCareCostTrendRateAssumedNextFIscalYearCatastrophicDrugBenefit": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next FIscal Year, Catastrophic Drug Benefit",
        "label": "Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next FIscal Year, Catastrophic Drug Benefit",
        "terseLabel": "Catastrophic drug benefit"
       }
      }
     },
     "localname": "DefinedBenefitPlanHealthCareCostTrendRateAssumedNextFIscalYearCatastrophicDrugBenefit",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "gww_DefinedBenefitPlanHealthCareCostTrendRateAssumedNextFiscalYearPostAge65": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year, Post Age 65",
        "label": "Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year, Post Age 65",
        "terseLabel": "Post age 65"
       }
      }
     },
     "localname": "DefinedBenefitPlanHealthCareCostTrendRateAssumedNextFiscalYearPostAge65",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "gww_DefinedBenefitPlanHealthCareCostTrendRateAssumedNextFiscalYearPreAge65": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year, Pre Age 65",
        "label": "Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year, Pre Age 65",
        "terseLabel": "Pre age 65"
       }
      }
     },
     "localname": "DefinedBenefitPlanHealthCareCostTrendRateAssumedNextFiscalYearPreAge65",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "gww_EmployeeBenefitsAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "EMPLOYEE BENEFITS [Abstract]",
        "label": "EMPLOYEE BENEFITS [Abstract]"
       }
      }
     },
     "localname": "EmployeeBenefitsAbstract",
     "nsuri": "http://www.grainger.com/20191231",
     "xbrltype": "stringItemType"
    },
    "gww_EmployeeRelatedLiabilitiesCurrentMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Employee Related Liabilities, Current [Member]",
        "label": "Employee Related Liabilities, Current [Member]",
        "terseLabel": "Employee Related Liabilities, Current [Member]"
       }
      }
     },
     "localname": "EmployeeRelatedLiabilitiesCurrentMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_EuroDenominatedBankTermLoanMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Unsecured five-year euro denominated bank term loan in connection with the acquisition of the Fabory Group [Member]",
        "label": "Euro Denominated Bank Term Loan [Member]",
        "terseLabel": "Euro term loan [Member]"
       }
      }
     },
     "localname": "EuroDenominatedBankTermLoanMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_EuroInterbankOfferedRateEURIBORMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Euro Interbank Offered Rate (EURIBOR) [Member]",
        "label": "Euro Interbank Offered Rate (EURIBOR) [Member]",
        "terseLabel": "Euro Interbank Offered Rate (EURIBOR) [Member]"
       }
      }
     },
     "localname": "EuroInterbankOfferedRateEURIBORMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_FidelityGovernmentMoneyMarketFundMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Fidelity Government Money Market Fund",
        "label": "Fidelity Government Money Market Fund [Member]",
        "terseLabel": "Fidelity Government Money Market Fund [Domain]"
       }
      }
     },
     "localname": "FidelityGovernmentMoneyMarketFundMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_FidelitySpartanUSEquityIndexFundMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The Fidelity Spartan US Equity Index Fund tracks the Standard and Poor's 500 Index (S and P 500).",
        "label": "Fidelity Spartan US Equity Index Fund [Member]",
        "terseLabel": "Fidelity Spartan US Equity Index Fund [Member]"
       }
      }
     },
     "localname": "FidelitySpartanUSEquityIndexFundMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_FurnitureFixturesMachineryEquipmentEstimatedUsefulLife": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Furniture, Fixtures, Machinery Equipment, Estimated Useful Life",
        "label": "Furniture, Fixtures, Machinery Equipment, Estimated Useful Life",
        "terseLabel": "Furniture, fixtures, machinery and equipment, estimated useful life"
       }
      }
     },
     "localname": "FurnitureFixturesMachineryEquipmentEstimatedUsefulLife",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "durationItemType"
    },
    "gww_FurnitureFixturesMachineryandEquipmentMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Furniture, Fixtures, Machinery and Equipment [Member]",
        "label": "Furniture, Fixtures, Machinery and Equipment [Member]",
        "terseLabel": "Furniture, fixtures, machinery and equipment [Member]"
       }
      }
     },
     "localname": "FurnitureFixturesMachineryandEquipmentMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/PropertyBuildingsAndEquipmentDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_GeographicalInformationAxis": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Geographical Information on Segment Footnote",
        "label": "Geographical Information [Axis]",
        "terseLabel": "Geographical Information [Axis]"
       }
      }
     },
     "localname": "GeographicalInformationAxis",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "gww_GeographicalInformationDomain": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "[Domain] for Geographical Information on Segment Footnote",
        "label": "Geographical Information [Domain]",
        "terseLabel": "Geographical Information [Domain]"
       }
      }
     },
     "localname": "GeographicalInformationDomain",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_GoodwillAndOtherIntangiblesAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "GOODWILL AND OTHER INTANGIBLES [Abstract]",
        "label": "GOODWILL AND OTHER INTANGIBLES [Abstract]"
       }
      }
     },
     "localname": "GoodwillAndOtherIntangiblesAbstract",
     "nsuri": "http://www.grainger.com/20191231",
     "xbrltype": "stringItemType"
    },
    "gww_GoodwillImpairmentLossRounded": {
     "auth_ref": [],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Goodwill, Impairment Loss, Rounded",
        "label": "Goodwill, Impairment Loss, Rounded",
        "terseLabel": "Goodwill, Impairment Loss, Rounded"
       }
      }
     },
     "localname": "GoodwillImpairmentLossRounded",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsAdditionalInformationDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "gww_GovernmentCustomerMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Government Customer [Member]",
        "label": "Government Customer [Member]",
        "terseLabel": "Government Customer [Member]"
       }
      }
     },
     "localname": "GovernmentCustomerMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_HealthcareCustomerMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Healthcare Customer [Member]",
        "label": "Healthcare Customer [Member]",
        "terseLabel": "Healthcare Customer [Member]"
       }
      }
     },
     "localname": "HealthcareCustomerMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_HeavyManufacturingMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Heavy Manufacturing [Member]",
        "label": "Heavy Manufacturing [Member]",
        "terseLabel": "Heavy Manufacturing [Member]"
       }
      }
     },
     "localname": "HeavyManufacturingMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_LightManufacturingMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Light Manufacturing [Member]",
        "label": "Light Manufacturing [Member]",
        "terseLabel": "Light Manufacturing [Member]"
       }
      }
     },
     "localname": "LightManufacturingMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_LocationsMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Locations",
        "label": "Locations [Member]",
        "terseLabel": "Geographical Information"
       }
      }
     },
     "localname": "LocationsMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_LongTermDebtCurrentMaturitiesFairValueDisclosure": {
     "auth_ref": [],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Long-Term Debt, Current Maturities, Fair Value Disclosure",
        "label": "Long-Term Debt, Current Maturities, Fair Value Disclosure",
        "negatedTerseLabel": "Long-Term Debt, Current Maturities, Fair Value Disclosure"
       }
      }
     },
     "localname": "LongTermDebtCurrentMaturitiesFairValueDisclosure",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "gww_LongTermDebtExcludingCurrentMaturitiesFairValueDisclosure": {
     "auth_ref": [],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Long-Term Debt, Excluding Current Maturities, Fair Value Disclosure",
        "label": "Long-Term Debt, Excluding Current Maturities, Fair Value Disclosure",
        "terseLabel": "Long-Term Debt, Excluding Current Maturities, Fair Value Disclosure"
       }
      }
     },
     "localname": "LongTermDebtExcludingCurrentMaturitiesFairValueDisclosure",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "gww_LongTermDebtGrossFairValueDisclosure": {
     "auth_ref": [],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Long-Term Debt, Gross, Fair Value Disclosure",
        "label": "Long-Term Debt, Gross, Fair Value Disclosure",
        "terseLabel": "Long-Term Debt, Gross, Fair Value Disclosure"
       }
      }
     },
     "localname": "LongTermDebtGrossFairValueDisclosure",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "gww_NaturalResourcesMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Natural Resources [Member]",
        "label": "Natural Resources [Member]",
        "terseLabel": "Natural Resources [Member]"
       }
      }
     },
     "localname": "NaturalResourcesMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_NetUnrecognizedGainsLossesAmortizationPeriod": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Represents the amortization period in years for unrecognized gains (losses) included in net periodic benefits costs, which is based on the average remaining service period for active plan participants expected to retire and receive benefits.",
        "label": "Net Unrecognized Gains (Losses) Amortization Period",
        "terseLabel": "Net unrecognized gains (losses), amortization period"
       }
      }
     },
     "localname": "NetUnrecognizedGainsLossesAmortizationPeriod",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "durationItemType"
    },
    "gww_Operatingleaseexpirationdate": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The latest expiration date of noncancellable operating leases.",
        "label": "OperatingLeaseExpirationDate",
        "terseLabel": "Operating Lease Expiration Date"
       }
      }
     },
     "localname": "Operatingleaseexpirationdate",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "gYearItemType"
    },
    "gww_OtherBusinessesMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Other businesses include the results of the following non-material operating segments: MonotaRO Co., Ltd. (Japan), Grainger, S.A. de C.V. (Mexico), Asia Pacific Brands India Private Limited (India), Grainger Carbie Inc. (Puerto Rico), Grainger China LLC (China) and Grainger Panama S.A. (Panama).",
        "label": "Other Businesses [Member]",
        "terseLabel": "Other businesses"
       }
      }
     },
     "localname": "OtherBusinessesMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsAdditionalInformationDetails",
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsBalancesAndChangesInCarryingAmountsOfGoodwillDetails",
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_OtherForeignCountriesMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Other foreign countries include the results of non-material operating segments that are not individually reportable.",
        "label": "Other Foreign Countries [Member]",
        "terseLabel": "Other foreign countries"
       }
      }
     },
     "localname": "OtherForeignCountriesMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_OtherLongTermDebtFairValueDisclosure": {
     "auth_ref": [],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Other Long-Term Debt, Fair Value Disclosure",
        "label": "Other Long-Term Debt, Fair Value Disclosure",
        "terseLabel": "Other Long-Term Debt, Fair Value Disclosure"
       }
      }
     },
     "localname": "OtherLongTermDebtFairValueDisclosure",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "gww_OtherMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Other [Member]",
        "label": "Other [Member]",
        "terseLabel": "Other [Member]"
       }
      }
     },
     "localname": "OtherMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_PercentageOfCompanyWideRevenue": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Percentage Of Company-Wide Revenue",
        "label": "Percentage Of Company-Wide Revenue",
        "terseLabel": "Percentage Of Company-Wide Revenue"
       }
      }
     },
     "localname": "PercentageOfCompanyWideRevenue",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "gww_PlanAssetsMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Plan Assets [Member]",
        "label": "Plan Assets [Member]",
        "terseLabel": "Plan Assets [Member]"
       }
      }
     },
     "localname": "PlanAssetsMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_ProfitSharingAutomaticContributionByEmployerPercentage": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Profit Sharing Automatic Contribution By Employer, Percentage",
        "label": "Profit Sharing Automatic Contribution By Employer, Percentage",
        "terseLabel": "Profit Sharing Automatic Contribution By Employer, Percentage",
        "verboseLabel": "Profit sharing automatic contribution percentage"
       }
      }
     },
     "localname": "ProfitSharingAutomaticContributionByEmployerPercentage",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsDefinedContributionPlansDetails",
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "gww_ProfitSharingContributionPercentage": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The contribution percentage range of total eligible compensation paid to all eligible employees under the Company's amended noncontributory profit sharing plan.",
        "label": "Profit Sharing Contribution Percentage",
        "terseLabel": "Profit Sharing Contribution Percentage",
        "verboseLabel": "Profit sharing contribution percentage"
       }
      }
     },
     "localname": "ProfitSharingContributionPercentage",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsDefinedContributionPlansDetails",
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "gww_REVENUEAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "REVENUE [Abstract]",
        "label": "REVENUE [Abstract]"
       }
      }
     },
     "localname": "REVENUEAbstract",
     "nsuri": "http://www.grainger.com/20191231",
     "xbrltype": "stringItemType"
    },
    "gww_RetailWholesaleMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Retail/Wholesale [Member]",
        "label": "Retail/Wholesale [Member]",
        "terseLabel": "Retail/Wholesale [Member]"
       }
      }
     },
     "localname": "RetailWholesaleMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_RevenueFromContractWithCustomerExcludingAssessedTaxPercentage": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Revenue From Contract With Customer, Excluding Assessed Tax, Percentage",
        "label": "Revenue From Contract With Customer, Excluding Assessed Tax, Percentage",
        "terseLabel": "Revenue From Contract With Customer, Excluding Assessed Tax, Percentage"
       }
      }
     },
     "localname": "RevenueFromContractWithCustomerExcludingAssessedTaxPercentage",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "gww_RevenueFromContractWithCustomerExcludingAssessedTaxPercentageOfCompanyWideRevenue": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Revenue From Contract With Customer, Excluding Assessed Tax, Percentage Of Company-Wide Revenue",
        "label": "Revenue From Contract With Customer, Excluding Assessed Tax, Percentage Of Company-Wide Revenue",
        "terseLabel": "Revenue From Contract With Customer, Excluding Assessed Tax, Percentage Of Company-Wide Revenue"
       }
      }
     },
     "localname": "RevenueFromContractWithCustomerExcludingAssessedTaxPercentageOfCompanyWideRevenue",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "gww_SegmentReportingInformationAssetsAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "",
        "label": "Segment Reporting Information Assets [Abstract]",
        "terseLabel": "Summarized Information:"
       }
      }
     },
     "localname": "SegmentReportingInformationAssetsAbstract",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "gww_SegmentReportingOtherReconcilingInformationTableTextBlock": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of significant reconciling items, including operating earnings and assets, from reportable segments to the entity's consolidated amounts.",
        "label": "SegmentReportingOtherReconcilingInformation [Table Text Block]",
        "terseLabel": "Significant Reconciling Items from Segments to Consolidated"
       }
      }
     },
     "localname": "SegmentReportingOtherReconcilingInformationTableTextBlock",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/SegmentInformationTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "gww_SelectedQuarterlyFinancialDataUnauditedAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) [Abstract]",
        "label": "SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) [Abstract]"
       }
      }
     },
     "localname": "SelectedQuarterlyFinancialDataUnauditedAbstract",
     "nsuri": "http://www.grainger.com/20191231",
     "xbrltype": "stringItemType"
    },
    "gww_ServiceFeeRevenue": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Grainger's Service Fee Revenue as a percentage of sales.",
        "label": "Service Fee Revenue",
        "terseLabel": "Service fee revenue (approximately)",
        "verboseLabel": "Service fee revenue"
       }
      }
     },
     "localname": "ServiceFeeRevenue",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/SegmentInformationDetails",
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "gww_ShareBasedCompensationVestedFairValue": {
     "auth_ref": [],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Share-Based Compensation Fair Value of Vested Restricted Stock Units",
        "label": "Share-Based Compensation Vested Fair Value",
        "terseLabel": "Fair value of shares vested"
       }
      }
     },
     "localname": "ShareBasedCompensationVestedFairValue",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "gww_StockIncentivePlansAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "STOCK INCENTIVE PLANS [Abstract]",
        "label": "STOCK INCENTIVE PLANS [Abstract]"
       }
      }
     },
     "localname": "StockIncentivePlansAbstract",
     "nsuri": "http://www.grainger.com/20191231",
     "xbrltype": "stringItemType"
    },
    "gww_StockIssuedDuringPeriodSharesPerformanceShareUnits": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Stock Issued During Period, Shares, Performance Share Units",
        "label": "Stock Issued During Period, Shares, Performance Share Units",
        "terseLabel": "Settlement of performance share units, net of 6,737, 1,027 and 9,334 shares retained, respectively (in shares)"
       }
      }
     },
     "localname": "StockIssuedDuringPeriodSharesPerformanceShareUnits",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/CapitalStockDetails"
     ],
     "xbrltype": "sharesItemType"
    },
    "gww_StockIssuedDuringPeriodSharesPerformanceShareUnitsRetained": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Stock Issued During Period, Shares, Performance Share Units, Retained",
        "label": "Stock Issued During Period, Shares, Performance Share Units, Retained",
        "terseLabel": "Shares retained after settlement of performance share units (in shares)"
       }
      }
     },
     "localname": "StockIssuedDuringPeriodSharesPerformanceShareUnitsRetained",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/CapitalStockDetails"
     ],
     "xbrltype": "sharesItemType"
    },
    "gww_StockIssuedDuringPeriodSharesRestrictedStockAwardRetained": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Stock Issued During Period, Shares, Restricted Stock Award, Retained",
        "label": "Stock Issued During Period, Shares, Restricted Stock Award, Retained",
        "terseLabel": "Shares retained after settlement of restricted stock units (in shares)"
       }
      }
     },
     "localname": "StockIssuedDuringPeriodSharesRestrictedStockAwardRetained",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/CapitalStockDetails"
     ],
     "xbrltype": "sharesItemType"
    },
    "gww_StockOptionsExercisedAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "-- None. No documentation exists for this element. --",
        "label": "Stock Options Exercised [Abstract]",
        "terseLabel": "Stock Options Exercised [Abstract]"
       }
      }
     },
     "localname": "StockOptionsExercisedAbstract",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "gww_SummaryOfSignificantAccountingPoliciesAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]",
        "label": "SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]"
       }
      }
     },
     "localname": "SummaryOfSignificantAccountingPoliciesAbstract",
     "nsuri": "http://www.grainger.com/20191231",
     "xbrltype": "stringItemType"
    },
    "gww_TaxCutsAndJobsActOf2017ReclassificationFromAOCIToRetainedEarnings": {
     "auth_ref": [],
     "calculation": {
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails": {
       "order": 3.0,
       "parentTag": "us-gaap_OtherComprehensiveIncomeLossNetOfTax",
       "weight": -1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tax Cuts And Jobs Act Of 2017, Reclassification From AOCI To Retained Earnings",
        "label": "Tax Cuts And Jobs Act Of 2017, Reclassification From AOCI To Retained Earnings",
        "negatedTerseLabel": "Amounts reclassified to Retained earnings"
       }
      }
     },
     "localname": "TaxCutsAndJobsActOf2017ReclassificationFromAOCIToRetainedEarnings",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "gww_TaxPositionsWithUncertainTimingOfDeductibility": {
     "auth_ref": [],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Other information relative to a tax position which it is highly certain that the total amount of the unrecognized tax benefit will significantly increase or decrease but the timing of deductibility is uncertain.",
        "label": "Tax Positions With Uncertain Timing Of Deductibility",
        "terseLabel": "Liability for tax uncertainties"
       }
      }
     },
     "localname": "TaxPositionsWithUncertainTimingOfDeductibility",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesChangesInLiabilityForTaxUncertaintiesExcludingInterestDetails",
      "http://www.grainger.com/role/IncomeTaxesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "gww_TermLoanMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Term Loan [Member]",
        "label": "Term Loan [Member]",
        "terseLabel": "Term loan [Member]"
       }
      }
     },
     "localname": "TermLoanMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_TotalRegisteredInvestmentCompaniesMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The total registered investment companies that pool funds from many investors to invest in a combination of underlying investments, primarily equity investments, which track the Standard and Poor's 500 Index (S and P 500).",
        "label": "Total Registered Investment Companies [Member]",
        "terseLabel": "Total Registered Investment Companies [Member]"
       }
      }
     },
     "localname": "TotalRegisteredInvestmentCompaniesMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_TransportationMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Transportation [Member]",
        "label": "Transportation [Member]",
        "terseLabel": "Transportation [Member]"
       }
      }
     },
     "localname": "TransportationMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_UnitedStatesAndCanadaSegmentsMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "United States And Canada Segments [Member]",
        "label": "United States And Canada Segments [Member]",
        "terseLabel": "United States and Canada"
       }
      }
     },
     "localname": "UnitedStatesAndCanadaSegmentsMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_UnsecuredSeniorNotes3.75Member": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Unsecured Senior Notes, 3.75% [Member]",
        "label": "Unsecured Senior Notes, 3.75% [Member]",
        "terseLabel": "Unsecured Senior Notes, 3.75% [Member]"
       }
      }
     },
     "localname": "UnsecuredSeniorNotes3.75Member",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_UnsecuredSeniorNotes4.20Member": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Unsecured Senior Notes, 4.20% [Member]",
        "label": "Unsecured Senior Notes, 4.20% [Member]",
        "terseLabel": "Unsecured Senior Notes, 4.20% [Member]"
       }
      }
     },
     "localname": "UnsecuredSeniorNotes4.20Member",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_UnsecuredSeniorNotes4.60Member": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Unsecured Senior Notes, 4.60% [Member]",
        "label": "Unsecured Senior Notes, 4.60% [Member]",
        "terseLabel": "Unsecured Senior Notes, 4.60% [Member]"
       }
      }
     },
     "localname": "UnsecuredSeniorNotes4.60Member",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_ValuationAllowanceIncreaseRelatedToU.S.ForeignTaxCreditsMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Valuation Allowance Increase Related To U.S. Foreign Tax Credits [Member]",
        "label": "Valuation Allowance Increase Related To U.S. Foreign Tax Credits [Member]",
        "terseLabel": "Valuation allowance increase related to U.S. foreign tax credits [Member]"
       }
      }
     },
     "localname": "ValuationAllowanceIncreaseRelatedToU.S.ForeignTaxCreditsMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesChangesInValuationAllowanceDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_ValuationAllowanceIncreaseRelatedtoForeignNetOperatingLossCarryforwardsMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Valuation Allowance, Increase Related to Foreign Net Operating Loss Carryforwards [Member]",
        "label": "Valuation Allowance, Increase Related to Foreign Net Operating Loss Carryforwards [Member]",
        "terseLabel": "Valuation allowance increases primarily related to foreign NOLs [Member]"
       }
      }
     },
     "localname": "ValuationAllowanceIncreaseRelatedtoForeignNetOperatingLossCarryforwardsMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesChangesInValuationAllowanceDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_ValuationAllowanceReleasesRelatedtoForeignNetOperatingLossCarryforwardsMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Valuation Allowance, Releases Related to Foreign Net Operating Loss Carryforwards [Member]",
        "label": "Valuation Allowance, Releases Related to Foreign Net Operating Loss Carryforwards [Member]",
        "terseLabel": "Valuation allowance releases related to foreign NOLs [Member]"
       }
      }
     },
     "localname": "ValuationAllowanceReleasesRelatedtoForeignNetOperatingLossCarryforwardsMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesChangesInValuationAllowanceDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_Vanguard500IndexFundMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The Vanguard 500 Index Fund tracks the Standard and Poor's 500 Index (S and P 500).",
        "label": "Vanguard 500 Index Fund [Member]",
        "terseLabel": "Vanguard 500 Index Fund [Member]"
       }
      }
     },
     "localname": "Vanguard500IndexFundMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_VanguardFederalMoneyMarketFundMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Vanguard Federal Money Market Fund [Member]",
        "label": "Vanguard Federal Money Market Fund [Member]",
        "terseLabel": "Vanguard Federal Money Market Fund [Member]"
       }
      }
     },
     "localname": "VanguardFederalMoneyMarketFundMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_VanguardTotalInternationalStockMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "International fund that tracks stock markets countries around the world, except United States",
        "label": "Vanguard Total International Stock Member",
        "terseLabel": "Vanguard Total International Stock Member"
       }
      }
     },
     "localname": "VanguardTotalInternationalStockMember",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "gww_WeightedAveragePricePerShareAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "-- None. No documentation exists for this element. --",
        "label": "Weighted Average Price Per Share [Abstract]",
        "terseLabel": "Weighted Average Price Per Share [Abstract]"
       }
      }
     },
     "localname": "WeightedAveragePricePerShareAbstract",
     "nsuri": "http://www.grainger.com/20191231",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansDetails",
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "srt_ConsolidationEliminationsMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Consolidation, Eliminations [Member]",
        "terseLabel": "Unallocated in consolidation [Member]"
       }
      }
     },
     "localname": "ConsolidationEliminationsMember",
     "nsuri": "http://fasb.org/srt/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "srt_ConsolidationItemsAxis": {
     "auth_ref": [
      "r150",
      "r157"
     ],
     "lang": {
      "en-US": {
       "role": {
        "label": "Consolidation Items [Axis]",
        "terseLabel": "Consolidation Items [Axis]"
       }
      }
     },
     "localname": "ConsolidationItemsAxis",
     "nsuri": "http://fasb.org/srt/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails",
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "srt_ConsolidationItemsDomain": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Consolidation Items [Domain]",
        "terseLabel": "Consolidation Items [Domain]"
       }
      }
     },
     "localname": "ConsolidationItemsDomain",
     "nsuri": "http://fasb.org/srt/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails",
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "srt_MajorCustomersAxis": {
     "auth_ref": [
      "r162",
      "r243",
      "r248",
      "r463"
     ],
     "lang": {
      "en-US": {
       "role": {
        "label": "Customer [Axis]",
        "terseLabel": "Customer [Axis]"
       }
      }
     },
     "localname": "MajorCustomersAxis",
     "nsuri": "http://fasb.org/srt/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails",
      "http://www.grainger.com/role/RevenueTables"
     ],
     "xbrltype": "stringItemType"
    },
    "srt_MaximumMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Maximum [Member]",
        "terseLabel": "Maximum [Member]"
       }
      }
     },
     "localname": "MaximumMember",
     "nsuri": "http://fasb.org/srt/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsDefinedContributionPlansDetails",
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails",
      "http://www.grainger.com/role/LeasesNarrativeDetails",
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/StockIncentivePlansDetails",
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails",
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "srt_MinimumMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Minimum [Member]",
        "terseLabel": "Minimum [Member]"
       }
      }
     },
     "localname": "MinimumMember",
     "nsuri": "http://fasb.org/srt/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsDefinedContributionPlansDetails",
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails",
      "http://www.grainger.com/role/LeasesNarrativeDetails",
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/StockIncentivePlansDetails",
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails",
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "srt_NameOfMajorCustomerDomain": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Customer [Domain]",
        "terseLabel": "Customer [Domain]"
       }
      }
     },
     "localname": "NameOfMajorCustomerDomain",
     "nsuri": "http://fasb.org/srt/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails",
      "http://www.grainger.com/role/RevenueTables"
     ],
     "xbrltype": "domainItemType"
    },
    "srt_ProductOrServiceAxis": {
     "auth_ref": [
      "r159",
      "r243",
      "r246",
      "r460",
      "r461"
     ],
     "lang": {
      "en-US": {
       "role": {
        "label": "Product and Service [Axis]",
        "terseLabel": "Product and Service [Axis]"
       }
      }
     },
     "localname": "ProductOrServiceAxis",
     "nsuri": "http://fasb.org/srt/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails",
      "http://www.grainger.com/role/RevenueTables"
     ],
     "xbrltype": "stringItemType"
    },
    "srt_ProductsAndServicesDomain": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Product and Service [Domain]",
        "terseLabel": "Product and Service [Domain]"
       }
      }
     },
     "localname": "ProductsAndServicesDomain",
     "nsuri": "http://fasb.org/srt/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails",
      "http://www.grainger.com/role/RevenueTables"
     ],
     "xbrltype": "domainItemType"
    },
    "srt_RangeAxis": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Statistical Measurement [Axis]",
        "terseLabel": "Statistical Measurement [Axis]"
       }
      }
     },
     "localname": "RangeAxis",
     "nsuri": "http://fasb.org/srt/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsDefinedContributionPlansDetails",
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails",
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails",
      "http://www.grainger.com/role/LeasesNarrativeDetails",
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/StockIncentivePlansDetails",
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails",
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "srt_RangeMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Statistical Measurement [Domain]",
        "terseLabel": "Statistical Measurement [Domain]"
       }
      }
     },
     "localname": "RangeMember",
     "nsuri": "http://fasb.org/srt/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsDefinedContributionPlansDetails",
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails",
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails",
      "http://www.grainger.com/role/LeasesNarrativeDetails",
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/StockIncentivePlansDetails",
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails",
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "srt_ScenarioUnspecifiedDomain": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Scenario [Domain]",
        "terseLabel": "Scenario [Domain]"
       }
      }
     },
     "localname": "ScenarioUnspecifiedDomain",
     "nsuri": "http://fasb.org/srt/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "srt_SegmentGeographicalDomain": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Geographical [Domain]",
        "terseLabel": "Geographical [Domain]",
        "verboseLabel": "Geographical [Domain]"
       }
      }
     },
     "localname": "SegmentGeographicalDomain",
     "nsuri": "http://fasb.org/srt/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsAdditionalInformationDetails",
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsBalancesAndChangesInCarryingAmountsOfGoodwillDetails",
      "http://www.grainger.com/role/RevenueDetails",
      "http://www.grainger.com/role/RevenueTables",
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "srt_StatementGeographicalAxis": {
     "auth_ref": [
      "r161",
      "r243",
      "r247",
      "r462",
      "r466",
      "r470"
     ],
     "lang": {
      "en-US": {
       "role": {
        "label": "Geographical [Axis]",
        "terseLabel": "Geographical [Axis]",
        "verboseLabel": "Geographical [Axis]"
       }
      }
     },
     "localname": "StatementGeographicalAxis",
     "nsuri": "http://fasb.org/srt/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsAdditionalInformationDetails",
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsBalancesAndChangesInCarryingAmountsOfGoodwillDetails",
      "http://www.grainger.com/role/RevenueDetails",
      "http://www.grainger.com/role/RevenueTables",
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "srt_StatementScenarioAxis": {
     "auth_ref": [
      "r223",
      "r421"
     ],
     "lang": {
      "en-US": {
       "role": {
        "label": "Scenario [Axis]",
        "terseLabel": "Scenario [Axis]"
       }
      }
     },
     "localname": "StatementScenarioAxis",
     "nsuri": "http://fasb.org/srt/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "srt_WeightedAverageMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Weighted Average [Member]",
        "terseLabel": "Weighted average [Member]"
       }
      }
     },
     "localname": "WeightedAverageMember",
     "nsuri": "http://fasb.org/srt/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_AccountsPayableTradeCurrentAndNoncurrent": {
     "auth_ref": [
      "r436",
      "r456"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 3.0,
       "parentTag": "us-gaap_LiabilitiesCurrent",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Carrying value as of the balance sheet date of obligations incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business.",
        "label": "Accounts Payable, Trade",
        "terseLabel": "Trade accounts payable"
       }
      }
     },
     "localname": "AccountsPayableTradeCurrentAndNoncurrent",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_AccountsReceivableNetCurrent": {
     "auth_ref": [
      "r3",
      "r22",
      "r164",
      "r165",
      "r244"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 5.0,
       "parentTag": "us-gaap_AssetsCurrent",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.",
        "label": "Accounts Receivable, after Allowance for Credit Loss, Current",
        "terseLabel": "Accounts receivable (less allowance for doubtful accounts of $21 million and $25 million, respectively)"
       }
      }
     },
     "localname": "AccountsReceivableNetCurrent",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_AccruedIncomeTaxesCurrent": {
     "auth_ref": [
      "r15",
      "r430",
      "r448"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 7.0,
       "parentTag": "us-gaap_LiabilitiesCurrent",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Carrying amount as of the balance sheet date of the unpaid sum of the known and estimated amounts payable to satisfy all currently due domestic and foreign income tax obligations.",
        "label": "Accrued Income Taxes, Current",
        "terseLabel": "Income taxes payable"
       }
      }
     },
     "localname": "AccruedIncomeTaxesCurrent",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_AccruedLiabilitiesCurrentAndNoncurrent": {
     "auth_ref": [
      "r436",
      "r456"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 6.0,
       "parentTag": "us-gaap_LiabilitiesCurrent",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities.",
        "label": "Accrued Liabilities",
        "terseLabel": "Accrued expenses"
       }
      }
     },
     "localname": "AccruedLiabilitiesCurrentAndNoncurrent",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_AccumulatedDefinedBenefitPlansAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember": {
     "auth_ref": [
      "r54",
      "r60",
      "r63",
      "r282",
      "r381"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Accumulated other comprehensive (income) loss related to defined benefit plans including the portion attributable to the noncontrolling interest.",
        "label": "Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest [Member]",
        "terseLabel": "Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest [Member]"
       }
      }
     },
     "localname": "AccumulatedDefinedBenefitPlansAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment": {
     "auth_ref": [
      "r34",
      "r208"
     ],
     "calculation": {
      "http://www.grainger.com/role/PropertyBuildingsAndEquipmentDetails": {
       "order": 2.0,
       "parentTag": "us-gaap_PropertyPlantAndEquipmentNet",
       "weight": -1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.",
        "label": "Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment",
        "terseLabel": "Less: Accumulated depreciation and amortization"
       }
      }
     },
     "localname": "AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/PropertyBuildingsAndEquipmentDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_AccumulatedForeignCurrencyAdjustmentAttributableToNoncontrollingInterestMember": {
     "auth_ref": [
      "r52",
      "r60",
      "r381"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Accumulated other comprehensive income (loss) resulting from foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature, attributable to the noncontrolling interest.",
        "label": "Accumulated Foreign Currency Adjustment Attributable to Noncontrolling Interest [Member]",
        "terseLabel": "Noncontrolling Interest [Member]"
       }
      }
     },
     "localname": "AccumulatedForeignCurrencyAdjustmentAttributableToNoncontrollingInterestMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_AccumulatedForeignCurrencyAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember": {
     "auth_ref": [
      "r52",
      "r60",
      "r63",
      "r381"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Accumulated other comprehensive income (loss) resulting from foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature, including the portion attributable to the noncontrolling interest.",
        "label": "Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member]",
        "terseLabel": "Foreign Currency Translation and Other"
       }
      }
     },
     "localname": "AccumulatedForeignCurrencyAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax": {
     "auth_ref": [
      "r55",
      "r60"
     ],
     "calculation": {
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount, after tax, of accumulated other comprehensive (income) loss for defined benefit plan, that has not been recognized in net periodic benefit cost (credit).",
        "label": "Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax",
        "negatedTotalLabel": "Net accumulated gains"
       }
      }
     },
     "localname": "AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.",
        "label": "Accumulated Other Comprehensive Income (Loss) [Line Items]",
        "terseLabel": "Accumulated Other Comprehensive Income (Loss) [Line Items]"
       }
      }
     },
     "localname": "AccumulatedOtherComprehensiveIncomeLossLineItems",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax": {
     "auth_ref": [
      "r57",
      "r59",
      "r60"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 5.0,
       "parentTag": "us-gaap_StockholdersEquity",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.",
        "label": "Accumulated Other Comprehensive Income (Loss), Net of Tax",
        "terseLabel": "Accumulated other comprehensive losses"
       }
      }
     },
     "localname": "AccumulatedOtherComprehensiveIncomeLossNetOfTax",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_AccumulatedOtherComprehensiveIncomeLossTable": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of information about components of accumulated other comprehensive income (loss).",
        "label": "Accumulated Other Comprehensive Income (Loss) [Table]",
        "terseLabel": "Accumulated Other Comprehensive Income (Loss) [Table]"
       }
      }
     },
     "localname": "AccumulatedOtherComprehensiveIncomeLossTable",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_AccumulatedOtherComprehensiveIncomeMember": {
     "auth_ref": [
      "r56",
      "r60",
      "r63",
      "r381"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Accumulated increase (decrease) in equity from transactions and other events and circumstances from non-owner sources, attributable to the parent. Excludes net income (loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners.",
        "label": "AOCI Attributable to Parent [Member]",
        "terseLabel": "AOCE Attributable to W.W. Grainger, Inc.",
        "verboseLabel": "Accumulated Other Comprehensive Income (Loss) [Member]"
       }
      }
     },
     "localname": "AccumulatedOtherComprehensiveIncomeMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails",
      "http://www.grainger.com/role/ConsolidatedStatementsOfShareholdersEquity",
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_AdditionalPaidInCapitalCommonStock": {
     "auth_ref": [
      "r23"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 3.0,
       "parentTag": "us-gaap_StockholdersEquity",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Value received from shareholders in common stock-related transactions that are in excess of par value or stated value and amounts received from other stock-related transactions. Includes only common stock transactions (excludes preferred stock transactions). May be called contributed capital, capital in excess of par, capital surplus, or paid-in capital.",
        "label": "Additional Paid in Capital, Common Stock",
        "terseLabel": "Additional contributed capital"
       }
      }
     },
     "localname": "AdditionalPaidInCapitalCommonStock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_AdditionalPaidInCapitalMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Excess of issue price over par or stated value of the entity's capital stock and amounts received from other transactions involving the entity's stock or stockholders.",
        "label": "Additional Paid-in Capital [Member]",
        "terseLabel": "Additional Paid-in Capital [Member]"
       }
      }
     },
     "localname": "AdditionalPaidInCapitalMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfShareholdersEquity"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis": {
     "auth_ref": [
      "r122"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by type of change in accounting principle. Does not include error corrections.",
        "label": "Adjustments for Change in Accounting Principle [Axis]",
        "terseLabel": "Adjustments for Change in Accounting Principle [Axis]"
       }
      }
     },
     "localname": "AdjustmentsForChangeInAccountingPrincipleAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities": {
     "auth_ref": [
      "r102"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The aggregate amount of adjustments to net income or loss necessary to remove the effects of all items whose cash effects are investing or financing cash flows. The aggregate amount also includes all noncash expenses and income items which reduce or increase net income and are thus added back or deducted when calculating cash provided by or used in operating activities.",
        "label": "Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities",
        "terseLabel": "Subtotal"
       }
      }
     },
     "localname": "AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivities",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition": {
     "auth_ref": [],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of increase in additional paid-in capital (APIC) for recognition of cost for employee stock purchase program (ESPP) award under share-based payment arrangement.",
        "label": "APIC, Share-based Payment Arrangement, ESPP, Increase for Cost Recognition",
        "terseLabel": "Stock based compensation"
       }
      }
     },
     "localname": "AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfShareholdersEquity"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_AdvertisingCostsPolicyTextBlock": {
     "auth_ref": [
      "r324"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of accounting policy for advertising cost.",
        "label": "Advertising Cost [Policy Text Block]",
        "terseLabel": "ADVERTISING"
       }
      }
     },
     "localname": "AdvertisingCostsPolicyTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_AdvertisingExpense": {
     "auth_ref": [
      "r325"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line.",
        "label": "Advertising Expense",
        "terseLabel": "Advertising expense"
       }
      }
     },
     "localname": "AdvertisingExpense",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_AllOtherSegmentsMember": {
     "auth_ref": [
      "r143",
      "r144",
      "r145",
      "r146",
      "r147",
      "r148"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Operating segments classified as other. Excludes intersegment elimination and reconciling items.",
        "label": "Other Segments [Member]",
        "terseLabel": "Other businesses"
       }
      }
     },
     "localname": "AllOtherSegmentsMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_AllocatedShareBasedCompensationExpense": {
     "auth_ref": [
      "r303",
      "r317",
      "r321"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.",
        "label": "Share-based Payment Arrangement, Expense",
        "terseLabel": "Pretax stock-based compensation expense"
       }
      }
     },
     "localname": "AllocatedShareBasedCompensationExpense",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent": {
     "auth_ref": [
      "r28",
      "r167",
      "r172"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of allowance for credit loss on accounts receivable, classified as current.",
        "label": "Accounts Receivable, Allowance for Credit Loss, Current",
        "terseLabel": "Allowance for doubtful accounts"
       }
      }
     },
     "localname": "AllowanceForDoubtfulAccountsReceivableCurrent",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheetsParentheticals"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_AmortizationOfIntangibleAssets": {
     "auth_ref": [
      "r102",
      "r191",
      "r197"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.",
        "label": "Amortization of Intangible Assets",
        "terseLabel": "Amortization expense, intangible assets"
       }
      }
     },
     "localname": "AmortizationOfIntangibleAssets",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsAdditionalInformationDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_AociAttributableToNoncontrollingInterestMember": {
     "auth_ref": [
      "r56",
      "r60",
      "r381"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Accumulated increase (decrease) in equity from transactions and other events and circumstances from non-owner sources, attributable to the noncontrolling interest. Excludes net income (loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners.",
        "label": "AOCI Attributable to Noncontrolling Interest [Member]",
        "terseLabel": "AOCI Attributable to Noncontrolling Interest [Member]"
       }
      }
     },
     "localname": "AociAttributableToNoncontrollingInterestMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestMember": {
     "auth_ref": [
      "r56",
      "r60",
      "r63",
      "r381"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Accumulated change in equity from transactions and other events and circumstances from non-owner sources, including the portion attributable to the noncontrolling interest. Excludes net income (loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners.",
        "label": "AOCI Including Portion Attributable to Noncontrolling Interest [Member]",
        "terseLabel": "AOCI Including Portion Attributable to Noncontrolling Interest [Member]"
       }
      }
     },
     "localname": "AociIncludingPortionAttributableToNoncontrollingInterestMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_Assets": {
     "auth_ref": [
      "r153",
      "r427",
      "r447"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.",
        "label": "Assets",
        "totalLabel": "TOTAL ASSETS",
        "verboseLabel": "Total assets"
       }
      }
     },
     "localname": "Assets",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets",
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_AssetsAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Assets [Abstract]",
        "terseLabel": "ASSETS"
       }
      }
     },
     "localname": "AssetsAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_AssetsCurrent": {
     "auth_ref": [
      "r5",
      "r7",
      "r51"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 3.0,
       "parentTag": "us-gaap_Assets",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Sum of the carrying amounts as of the balance sheet date of all assets that are expected to be realized in cash, sold, or consumed within one year (or the normal operating cycle, if longer). Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.",
        "label": "Assets, Current",
        "totalLabel": "Total current assets"
       }
      }
     },
     "localname": "AssetsCurrent",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_AssetsCurrentAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Assets, Current [Abstract]",
        "terseLabel": "CURRENT ASSETS"
       }
      }
     },
     "localname": "AssetsCurrentAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_AwardTypeAxis": {
     "auth_ref": [
      "r304",
      "r319"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by type of award under share-based payment arrangement.",
        "label": "Award Type [Axis]",
        "terseLabel": "Award Type [Axis]"
       }
      }
     },
     "localname": "AwardTypeAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansDetails",
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails",
      "http://www.grainger.com/role/StockIncentivePlansStockOptionsOutstandingAndExercisableDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_BalanceSheetLocationAxis": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by location on balance sheet (statement of financial position).",
        "label": "Balance Sheet Location [Axis]",
        "terseLabel": "Balance Sheet Location [Axis]"
       }
      }
     },
     "localname": "BalanceSheetLocationAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_BalanceSheetLocationDomain": {
     "auth_ref": [
      "r387",
      "r388"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Location in the balance sheet (statement of financial position).",
        "label": "Balance Sheet Location [Domain]",
        "terseLabel": "Balance Sheet Location [Domain]"
       }
      }
     },
     "localname": "BalanceSheetLocationDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_BuildingAndBuildingImprovementsMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Facility held for productive use including, but not limited to, office, production, storage and distribution facilities and any addition, improvement, or renovation to the structure, for example, but not limited to, interior masonry, interior flooring, electrical, and plumbing.",
        "label": "Building and Building Improvements [Member]",
        "terseLabel": "Building, structures and improvements [Member]"
       }
      }
     },
     "localname": "BuildingAndBuildingImprovementsMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/PropertyBuildingsAndEquipmentDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_BusinessAcquisitionAcquireeDomain": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Identification of the acquiree in a material business combination (or series of individually immaterial business combinations), which may include the name or other type of identification of the acquiree.",
        "label": "Business Acquisition, Acquiree [Domain]",
        "terseLabel": "Business Acquisition, Acquiree [Domain]"
       }
      }
     },
     "localname": "BusinessAcquisitionAcquireeDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_BusinessAcquisitionAxis": {
     "auth_ref": [
      "r365",
      "r366"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by business combination or series of individually immaterial business combinations.",
        "label": "Business Acquisition [Axis]",
        "terseLabel": "Business Acquisition [Axis]"
       }
      }
     },
     "localname": "BusinessAcquisitionAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_CashAndCashEquivalentsAtCarryingValue": {
     "auth_ref": [
      "r1",
      "r31",
      "r104"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 1.0,
       "parentTag": "us-gaap_AssetsCurrent",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.",
        "label": "Cash and Cash Equivalents, at Carrying Value",
        "periodEndLabel": "Cash and cash equivalents at end of year",
        "periodStartLabel": "Cash and cash equivalents at beginning of year",
        "terseLabel": "Cash and cash equivalents"
       }
      }
     },
     "localname": "CashAndCashEquivalentsAtCarryingValue",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets",
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease": {
     "auth_ref": [],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of increase (decrease) in cash and cash equivalents. Cash and cash equivalents are the amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Includes effect from exchange rate changes.",
        "label": "Cash and Cash Equivalents, Period Increase (Decrease)",
        "totalLabel": "NET CHANGE IN CASH AND CASH EQUIVALENTS:"
       }
      }
     },
     "localname": "CashAndCashEquivalentsPeriodIncreaseDecrease",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_CashAndCashEquivalentsPolicyTextBlock": {
     "auth_ref": [
      "r9",
      "r106",
      "r108"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of accounting policy for cash and cash equivalents, including the policy for determining which items are treated as cash equivalents. Other information that may be disclosed includes (1) the nature of any restrictions on the entity's use of its cash and cash equivalents, (2) whether the entity's cash and cash equivalents are insured or expose the entity to credit risk, (3) the classification of any negative balance accounts (overdrafts), and (4) the carrying basis of cash equivalents (for example, at cost) and whether the carrying amount of cash equivalents approximates fair value.",
        "label": "Cash and Cash Equivalents, Policy [Policy Text Block]",
        "terseLabel": "CASH AND CASH EQUIVALENTS"
       }
      }
     },
     "localname": "CashAndCashEquivalentsPolicyTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ChangeInAccountingPrincipleMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "A change from one generally accepted accounting principle to another generally accepted accounting principle when there are two or more generally accepted accounting principles that apply or when the accounting principle formerly used is no longer generally accepted. A change in the method of applying an accounting principle that is not treated as a change in accounting estimate also is considered a change in accounting principle.",
        "label": "Adjustments for Change in Accounting Principle [Domain]",
        "terseLabel": "Adjustments for Change in Accounting Principle [Domain]"
       }
      }
     },
     "localname": "ChangeInAccountingPrincipleMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_CommercialPaper": {
     "auth_ref": [
      "r12",
      "r428",
      "r451"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days.",
        "label": "Commercial Paper",
        "terseLabel": "Commercial paper"
       }
      }
     },
     "localname": "CommercialPaper",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails",
      "http://www.grainger.com/role/ShortTermDebtDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_CommercialPaperMember": {
     "auth_ref": [
      "r226"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Unsecured promissory note (generally negotiable) that provides institutions with short-term funds.",
        "label": "Commercial Paper [Member]",
        "terseLabel": "Commercial Paper [Member]"
       }
      }
     },
     "localname": "CommercialPaperMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ShortTermDebtDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_CommitmentsAndContingenciesPolicyTextBlock": {
     "auth_ref": [
      "r108",
      "r225",
      "r467",
      "r468"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of accounting policy for commitments and contingencies, which may include policies for recognizing and measuring loss and gain contingencies.",
        "label": "Commitments and Contingencies, Policy [Policy Text Block]",
        "terseLabel": "CONTINGENCIES"
       }
      }
     },
     "localname": "CommitmentsAndContingenciesPolicyTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_CommonStockDividendsPerShareCashPaid": {
     "auth_ref": [
      "r238"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Aggregate dividends paid during the period for each share of common stock outstanding.",
        "label": "Common Stock, Dividends, Per Share, Cash Paid",
        "terseLabel": "Cash dividends paid per share (in dollars per share)"
       }
      }
     },
     "localname": "CommonStockDividendsPerShareCashPaid",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfShareholdersEquityParentheticals"
     ],
     "xbrltype": "perShareItemType"
    },
    "us-gaap_CommonStockMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Stock that is subordinate to all other stock of the issuer.",
        "label": "Common Stock [Member]",
        "terseLabel": "Common Stock [Member]",
        "verboseLabel": "Outstanding Common Stock [Member]"
       }
      }
     },
     "localname": "CommonStockMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/CapitalStockDetails",
      "http://www.grainger.com/role/ConsolidatedStatementsOfShareholdersEquity"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_CommonStockParOrStatedValuePerShare": {
     "auth_ref": [
      "r21"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Face amount or stated value per share of common stock.",
        "label": "Common Stock, Par or Stated Value Per Share",
        "terseLabel": "Common stock, par value (in dollars per share)"
       }
      }
     },
     "localname": "CommonStockParOrStatedValuePerShare",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheetsParentheticals"
     ],
     "xbrltype": "perShareItemType"
    },
    "us-gaap_CommonStockSharesAuthorized": {
     "auth_ref": [
      "r21"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The maximum number of common shares permitted to be issued by an entity's charter and bylaws.",
        "label": "Common Stock, Shares Authorized",
        "terseLabel": "Common stock, shares authorized (in shares)"
       }
      }
     },
     "localname": "CommonStockSharesAuthorized",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheetsParentheticals"
     ],
     "xbrltype": "sharesItemType"
    },
    "us-gaap_CommonStockSharesIssued": {
     "auth_ref": [
      "r21"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.",
        "label": "Common Stock, Shares, Issued",
        "terseLabel": "Common stock, shares issued (in shares)"
       }
      }
     },
     "localname": "CommonStockSharesIssued",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheetsParentheticals"
     ],
     "xbrltype": "sharesItemType"
    },
    "us-gaap_CommonStockSharesOutstanding": {
     "auth_ref": [
      "r21",
      "r233"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.",
        "label": "Common Stock, Shares, Outstanding",
        "periodEndLabel": "Balance at end of period, common stock (in shares)",
        "periodStartLabel": "Balance at beginning of period, common stock (in shares)"
       }
      }
     },
     "localname": "CommonStockSharesOutstanding",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/CapitalStockDetails"
     ],
     "xbrltype": "sharesItemType"
    },
    "us-gaap_CommonStockValue": {
     "auth_ref": [
      "r21"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 2.0,
       "parentTag": "us-gaap_StockholdersEquity",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Aggregate par or stated value of issued nonredeemable common stock (or common stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable common shares, par value and other disclosure concepts are in another section within stockholders' equity.",
        "label": "Common Stock, Value, Issued",
        "terseLabel": "Common Stock \u2013 $0.50 par value \u2013 300,000,000 shares authorized; issued 109,659,219 shares"
       }
      }
     },
     "localname": "CommonStockValue",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_ComprehensiveIncomeNetOfTax": {
     "auth_ref": [
      "r66",
      "r68",
      "r69"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.",
        "label": "Comprehensive Income (Loss), Net of Tax, Attributable to Parent",
        "totalLabel": "Comprehensive earnings attributable to W.W. Grainger, Inc."
       }
      }
     },
     "localname": "ComprehensiveIncomeNetOfTax",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest": {
     "auth_ref": [
      "r66",
      "r68",
      "r372",
      "r373",
      "r384"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income (loss) and other comprehensive income (loss), attributable to noncontrolling interests. Excludes changes in equity resulting from investments by owners and distributions to owners.",
        "label": "Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest",
        "totalLabel": "Total comprehensive earnings (losses) attributable to noncontrolling interest"
       }
      }
     },
     "localname": "ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest": {
     "auth_ref": [
      "r66",
      "r68",
      "r371",
      "r384"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings": {
       "order": 1.0,
       "parentTag": "us-gaap_ComprehensiveIncomeNetOfTax",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income. Excludes changes in equity resulting from investments by owners and distributions to owners.",
        "label": "Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest",
        "totalLabel": "Comprehensive earnings, net of tax"
       }
      }
     },
     "localname": "ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterestAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]",
        "terseLabel": "Less: Comprehensive earnings (losses) attributable to noncontrolling interest"
       }
      }
     },
     "localname": "ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterestAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_ComprehensiveIncomeNoteTextBlock": {
     "auth_ref": [
      "r82"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The entire disclosure for comprehensive income, which includes, but is not limited to, 1) the amount of income tax expense or benefit allocated to each component of other comprehensive income, including reclassification adjustments, 2) the reclassification adjustments for each classification of other comprehensive income and 3) the ending accumulated balances for each component of comprehensive income.",
        "label": "Comprehensive Income (Loss) Note [Text Block]",
        "terseLabel": "ACCUMULATED OTHER COMPREHENSIVE EARNINGS (LOSSES) (AOCE)"
       }
      }
     },
     "localname": "ComprehensiveIncomeNoteTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoce"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ComprehensiveIncomePolicyPolicyTextBlock": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of accounting policy for comprehensive income.",
        "label": "Comprehensive Income, Policy [Policy Text Block]",
        "terseLabel": "OTHER COMPREHENSIVE EARNINGS (LOSSES)"
       }
      }
     },
     "localname": "ComprehensiveIncomePolicyPolicyTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ConcentrationRiskCreditRisk": {
     "auth_ref": [
      "r137",
      "r444"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of accounting policy for credit risk.",
        "label": "Concentration Risk, Credit Risk, Policy [Policy Text Block]",
        "terseLabel": "CONCENTRATION OF CREDIT RISK"
       }
      }
     },
     "localname": "ConcentrationRiskCreditRisk",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ConsolidationPolicyTextBlock": {
     "auth_ref": [
      "r108",
      "r375",
      "r385",
      "r386"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of accounting policy regarding (1) the principles it follows in consolidating or combining the separate financial statements, including the principles followed in determining the inclusion or exclusion of subsidiaries or other entities in the consolidated or combined financial statements and (2) its treatment of interests (for example, common stock, a partnership interest or other means of exerting influence) in other entities, for example consolidation or use of the equity or cost methods of accounting.  The accounting policy may also address the accounting treatment for intercompany accounts and transactions, noncontrolling interest, and the income statement treatment in consolidation for issuances of stock by a subsidiary.",
        "label": "Consolidation, Policy [Policy Text Block]",
        "terseLabel": "PRINCIPLES OF CONSOLIDATION"
       }
      }
     },
     "localname": "ConsolidationPolicyTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ContractWithCustomerBasisOfPricingAxis": {
     "auth_ref": [
      "r249"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by basis of pricing for contract representing right to consideration in exchange for good or service transferred to customer.",
        "label": "Contract with Customer, Basis of Pricing [Axis]",
        "terseLabel": "Contract with Customer, Basis of Pricing [Axis]"
       }
      }
     },
     "localname": "ContractWithCustomerBasisOfPricingAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails",
      "http://www.grainger.com/role/RevenueTables"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_ContractWithCustomerBasisOfPricingDomain": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Basis of pricing for contract with customer. Includes, but is not limited to, fixed-price and time-and-materials contracts.",
        "label": "Contract with Customer, Basis of Pricing [Domain]",
        "terseLabel": "Contract with Customer, Basis of Pricing [Domain]"
       }
      }
     },
     "localname": "ContractWithCustomerBasisOfPricingDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails",
      "http://www.grainger.com/role/RevenueTables"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_ContractWithCustomerDurationAxis": {
     "auth_ref": [
      "r250"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by duration of contract with customer. Includes, but is not limited to, short-term and long-term contracts.",
        "label": "Contract with Customer, Duration [Axis]",
        "terseLabel": "Contract with Customer, Duration [Axis]"
       }
      }
     },
     "localname": "ContractWithCustomerDurationAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails",
      "http://www.grainger.com/role/RevenueTables"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_ContractWithCustomerDurationDomain": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Duration of contract with customer. Includes, but is not limited to, short-term and long-term contracts.",
        "label": "Contract with Customer, Duration [Domain]",
        "terseLabel": "Contract with Customer, Duration [Domain]"
       }
      }
     },
     "localname": "ContractWithCustomerDurationDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails",
      "http://www.grainger.com/role/RevenueTables"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_ContractWithCustomerRefundLiability": {
     "auth_ref": [
      "r245"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of liability for consideration received or receivable from customer which is not included in transaction price, when consideration is expected to be refunded to customer.",
        "label": "Contract with Customer, Refund Liability",
        "terseLabel": "Accrued sales returns"
       }
      }
     },
     "localname": "ContractWithCustomerRefundLiability",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_ContractWithCustomerSalesChannelAxis": {
     "auth_ref": [
      "r252"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by sales channel for delivery of good or service in contract with customer.",
        "label": "Contract with Customer, Sales Channel [Axis]",
        "terseLabel": "Contract with Customer, Sales Channel [Axis]"
       }
      }
     },
     "localname": "ContractWithCustomerSalesChannelAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails",
      "http://www.grainger.com/role/RevenueTables"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_ContractWithCustomerSalesChannelDomain": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Sales channel for delivery of good or service in contract with customer. Includes, but is not limited to, directly to consumer and through intermediary.",
        "label": "Contract with Customer, Sales Channel [Domain]",
        "terseLabel": "Contract with Customer, Sales Channel [Domain]"
       }
      }
     },
     "localname": "ContractWithCustomerSalesChannelDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails",
      "http://www.grainger.com/role/RevenueTables"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_CostOfGoodsAndServicesSold": {
     "auth_ref": [
      "r77"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings": {
       "order": 2.0,
       "parentTag": "us-gaap_GrossProfit",
       "weight": -1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The aggregate costs related to goods produced and sold and services rendered by an entity during the reporting period. This excludes costs incurred during the reporting period related to financial services rendered and other revenue generating activities.",
        "label": "Cost of Goods and Services Sold",
        "terseLabel": "Cost of goods sold",
        "verboseLabel": "Cost of goods sold"
       }
      }
     },
     "localname": "CostOfGoodsAndServicesSold",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings",
      "http://www.grainger.com/role/SelectedQuarterlyFinancialDataUnauditedDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_CostOfSalesPolicyTextBlock": {
     "auth_ref": [
      "r254"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of accounting policy for cost of product sold and service rendered.",
        "label": "Cost of Goods and Service [Policy Text Block]",
        "terseLabel": "COST OF GOODS SOLD"
       }
      }
     },
     "localname": "CostOfSalesPolicyTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_CreditFacilityAxis": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by type of credit facility. Credit facilities provide capital to borrowers without the need to structure a loan for each borrowing.",
        "label": "Credit Facility [Axis]",
        "terseLabel": "Credit Facility [Axis]"
       }
      }
     },
     "localname": "CreditFacilityAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/SubsequentEventDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_CreditFacilityDomain": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Type of credit facility. Credit facilities provide capital to borrowers without the need to structure a loan for each borrowing.",
        "label": "Credit Facility [Domain]",
        "terseLabel": "Credit Facility [Domain]"
       }
      }
     },
     "localname": "CreditFacilityDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/SubsequentEventDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_CurrentFederalTaxExpenseBenefit": {
     "auth_ref": [
      "r113",
      "r356",
      "r360"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesDetails": {
       "order": 1.0,
       "parentTag": "us-gaap_CurrentIncomeTaxExpenseBenefit",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of current federal tax expense (benefit) pertaining to income (loss) from continuing operations.",
        "label": "Current Federal Tax Expense (Benefit)",
        "terseLabel": "U.S. Federal"
       }
      }
     },
     "localname": "CurrentFederalTaxExpenseBenefit",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_CurrentForeignTaxExpenseBenefit": {
     "auth_ref": [
      "r118",
      "r359"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesDetails": {
       "order": 3.0,
       "parentTag": "us-gaap_CurrentIncomeTaxExpenseBenefit",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of current foreign income tax expense (benefit) pertaining to income (loss) from continuing operations.",
        "label": "Current Foreign Tax Expense (Benefit)",
        "terseLabel": "Foreign"
       }
      }
     },
     "localname": "CurrentForeignTaxExpenseBenefit",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_CurrentIncomeTaxExpenseBenefit": {
     "auth_ref": [
      "r113",
      "r356",
      "r360"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesDetails": {
       "order": 1.0,
       "parentTag": "us-gaap_IncomeTaxExpenseBenefit",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of current income tax expense (benefit) pertaining to taxable income (loss) from continuing operations.",
        "label": "Current Income Tax Expense (Benefit)",
        "totalLabel": "Total current"
       }
      }
     },
     "localname": "CurrentIncomeTaxExpenseBenefit",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Current Income Tax Expense (Benefit), Continuing Operations [Abstract]",
        "terseLabel": "Current income tax expense:"
       }
      }
     },
     "localname": "CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_CurrentStateAndLocalTaxExpenseBenefit": {
     "auth_ref": [
      "r113",
      "r356",
      "r360"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesDetails": {
       "order": 2.0,
       "parentTag": "us-gaap_CurrentIncomeTaxExpenseBenefit",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of current state and local tax expense (benefit) pertaining to income (loss) from continuing operations.",
        "label": "Current State and Local Tax Expense (Benefit)",
        "terseLabel": "U.S. State"
       }
      }
     },
     "localname": "CurrentStateAndLocalTaxExpenseBenefit",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_CustomerRelatedIntangibleAssetsMember": {
     "auth_ref": [
      "r367"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Customer-related asset, including, but not limited to, customer lists, and noncontractual customer relationships.",
        "label": "Customer-Related Intangible Assets [Member]",
        "terseLabel": "Customer lists and relationships [Member]"
       }
      }
     },
     "localname": "CustomerRelatedIntangibleAssetsMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_DebtDisclosureAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Debt Disclosure [Abstract]"
       }
      }
     },
     "localname": "DebtDisclosureAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "xbrltype": "stringItemType"
    },
    "us-gaap_DebtInstrumentAxis": {
     "auth_ref": [
      "r14",
      "r15",
      "r16",
      "r429",
      "r433",
      "r446"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by type of debt instrument, including, but not limited to, draws against credit facilities.",
        "label": "Debt Instrument [Axis]",
        "terseLabel": "Debt Instrument [Axis]"
       }
      }
     },
     "localname": "DebtInstrumentAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails",
      "http://www.grainger.com/role/ShortTermDebtDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_DebtInstrumentBasisSpreadOnVariableRate1": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Percentage points added to the reference rate to compute the variable rate on the debt instrument.",
        "label": "Debt Instrument, Basis Spread on Variable Rate",
        "terseLabel": "Basis points"
       }
      }
     },
     "localname": "DebtInstrumentBasisSpreadOnVariableRate1",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/ShortTermDebtDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "us-gaap_DebtInstrumentCarryingAmount": {
     "auth_ref": [
      "r16",
      "r229",
      "r433",
      "r446"
     ],
     "calculation": {
      "http://www.grainger.com/role/LongTermDebtScheduledAggregatePrincipalPaymentsDetails": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.",
        "label": "Long-term Debt, Gross",
        "totalLabel": "Total",
        "verboseLabel": "Long-term debt, gross"
       }
      }
     },
     "localname": "DebtInstrumentCarryingAmount",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails",
      "http://www.grainger.com/role/LongTermDebtScheduledAggregatePrincipalPaymentsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DebtInstrumentFaceAmount": {
     "auth_ref": [
      "r401",
      "r403"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Face (par) amount of debt instrument at time of issuance.",
        "label": "Debt Instrument, Face Amount",
        "terseLabel": "Face amount of debt"
       }
      }
     },
     "localname": "DebtInstrumentFaceAmount",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DebtInstrumentInterestRateDuringPeriod": {
     "auth_ref": [
      "r43",
      "r401"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The average effective interest rate during the reporting period.",
        "label": "Debt Instrument, Interest Rate During Period",
        "terseLabel": "Weighted average interest rate during the year"
       }
      }
     },
     "localname": "DebtInstrumentInterestRateDuringPeriod",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ShortTermDebtDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "us-gaap_DebtInstrumentInterestRateEffectivePercentage": {
     "auth_ref": [
      "r43",
      "r231",
      "r401"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.",
        "label": "Debt Instrument, Interest Rate, Effective Percentage",
        "terseLabel": "Effective interest rate"
       }
      }
     },
     "localname": "DebtInstrumentInterestRateEffectivePercentage",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "us-gaap_DebtInstrumentInterestRateStatedPercentage": {
     "auth_ref": [
      "r43"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Contractual interest rate for funds borrowed, under the debt agreement.",
        "label": "Debt Instrument, Interest Rate, Stated Percentage",
        "terseLabel": "Stated interest rate"
       }
      }
     },
     "localname": "DebtInstrumentInterestRateStatedPercentage",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails",
      "http://www.grainger.com/role/ShortTermDebtDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "us-gaap_DebtInstrumentLineItems": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.",
        "label": "Debt Instrument [Line Items]",
        "terseLabel": "Debt Instrument [Line Items]"
       }
      }
     },
     "localname": "DebtInstrumentLineItems",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_DebtInstrumentNameDomain": {
     "auth_ref": [
      "r44"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The name for the particular debt instrument or borrowing that distinguishes it from other debt instruments or borrowings, including draws against credit facilities.",
        "label": "Debt Instrument, Name [Domain]",
        "terseLabel": "Debt Instrument, Name [Domain]"
       }
      }
     },
     "localname": "DebtInstrumentNameDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails",
      "http://www.grainger.com/role/ShortTermDebtDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_DebtInstrumentPeriodicPaymentPrincipal": {
     "auth_ref": [
      "r44"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of the required periodic payments applied to principal.",
        "label": "Debt Instrument, Periodic Payment, Principal",
        "terseLabel": "Semi annual payments"
       }
      }
     },
     "localname": "DebtInstrumentPeriodicPaymentPrincipal",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DebtInstrumentRedemptionPeriodAxis": {
     "auth_ref": [
      "r441"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information about timing of debt redemption features under terms of the debt agreement.",
        "label": "Debt Instrument, Redemption, Period [Axis]",
        "terseLabel": "Debt Instrument, Redemption, Period [Axis]"
       }
      }
     },
     "localname": "DebtInstrumentRedemptionPeriodAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_DebtInstrumentRedemptionPeriodDomain": {
     "auth_ref": [
      "r441"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Period as defined under terms of the debt agreement for debt redemption features.",
        "label": "Debt Instrument, Redemption, Period [Domain]",
        "terseLabel": "Debt Instrument, Redemption, Period [Domain]"
       }
      }
     },
     "localname": "DebtInstrumentRedemptionPeriodDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_DebtInstrumentRedemptionPeriodOneMember": {
     "auth_ref": [
      "r441"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Period one representing most current period of debt redemption features under terms of the debt agreement.",
        "label": "Debt Instrument, Redemption, Period One [Member]",
        "terseLabel": "Debt redemption, period one [Member]"
       }
      }
     },
     "localname": "DebtInstrumentRedemptionPeriodOneMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_DebtInstrumentRedemptionPeriodTwoMember": {
     "auth_ref": [
      "r441"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Period two representing second most current period of debt redemption features under terms of the debt agreement.",
        "label": "Debt Instrument, Redemption, Period Two [Member]",
        "terseLabel": "Debt redemption, period two [Member]"
       }
      }
     },
     "localname": "DebtInstrumentRedemptionPeriodTwoMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_DebtInstrumentRedemptionPricePercentage": {
     "auth_ref": [
      "r441"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.",
        "label": "Debt Instrument, Redemption Price, Percentage",
        "terseLabel": "Debt redemption percentage"
       }
      }
     },
     "localname": "DebtInstrumentRedemptionPricePercentage",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "us-gaap_DebtInstrumentRepurchaseAmount": {
     "auth_ref": [],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Fair value amount of debt instrument that was repurchased.",
        "label": "Debt Instrument, Repurchase Amount",
        "terseLabel": "Partially funded repurchase amount"
       }
      }
     },
     "localname": "DebtInstrumentRepurchaseAmount",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DebtInstrumentRepurchasedFaceAmount": {
     "auth_ref": [],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Face (par) amount of the original debt instrument that was repurchased.",
        "label": "Debt Instrument, Repurchased Face Amount",
        "terseLabel": "Total repurchase amount previously announced"
       }
      }
     },
     "localname": "DebtInstrumentRepurchasedFaceAmount",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DebtInstrumentTable": {
     "auth_ref": [
      "r44",
      "r114",
      "r234",
      "r235",
      "r236",
      "r237",
      "r400",
      "r401",
      "r403",
      "r442"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "A table or schedule providing information pertaining to long-term debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the company, if longer.",
        "label": "Schedule of Long-term Debt Instruments [Table]",
        "terseLabel": "Schedule of Long-term Debt Instruments [Table]"
       }
      }
     },
     "localname": "DebtInstrumentTable",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_DebtInstrumentTerm": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.",
        "label": "Debt Instrument, Term",
        "terseLabel": "Debt, term"
       }
      }
     },
     "localname": "DebtInstrumentTerm",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/ShortTermDebtDetails",
      "http://www.grainger.com/role/SubsequentEventDetails"
     ],
     "xbrltype": "durationItemType"
    },
    "us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet": {
     "auth_ref": [
      "r230",
      "r402"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of unamortized debt discount (premium) and debt issuance costs.",
        "label": "Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net",
        "negatedLabel": "Debt issuance costs and discounts, net of amortization"
       }
      }
     },
     "localname": "DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DebtWeightedAverageInterestRate": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Weighted average interest rate of debt outstanding.",
        "label": "Debt, Weighted Average Interest Rate",
        "terseLabel": "Weighted average interest rate"
       }
      }
     },
     "localname": "DebtWeightedAverageInterestRate",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "us-gaap_DeferredFinanceCostsGross": {
     "auth_ref": [
      "r402"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.",
        "label": "Debt Issuance Costs, Gross",
        "terseLabel": "Debt issuance costs and discounts"
       }
      }
     },
     "localname": "DeferredFinanceCostsGross",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DeferredIncomeTaxAssetsNet": {
     "auth_ref": [
      "r351"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 6.0,
       "parentTag": "us-gaap_Assets",
       "weight": 1.0
      },
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetailsCalc2": {
       "order": 1.0,
       "parentTag": "us-gaap_DeferredTaxLiabilities",
       "weight": -1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount, after allocation of valuation allowances and deferred tax liability, of deferred tax asset attributable to deductible differences and carryforwards, with jurisdictional netting.",
        "label": "Deferred Income Tax Assets, Net",
        "terseLabel": "DEFERRED INCOME TAXES",
        "verboseLabel": "Noncurrent assets"
       }
      }
     },
     "localname": "DeferredIncomeTaxAssetsNet",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets",
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DeferredIncomeTaxExpenseBenefit": {
     "auth_ref": [
      "r102",
      "r113",
      "r358",
      "r360"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesDetails": {
       "order": 2.0,
       "parentTag": "us-gaap_IncomeTaxExpenseBenefit",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations.",
        "label": "Deferred Income Tax Expense (Benefit)",
        "terseLabel": "Deferred income tax expense"
       }
      }
     },
     "localname": "DeferredIncomeTaxExpenseBenefit",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DeferredIncomeTaxLiabilities": {
     "auth_ref": [
      "r18",
      "r19",
      "r347",
      "r431",
      "r445"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails": {
       "order": 1.0,
       "parentTag": "us-gaap_DeferredTaxLiabilities",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of deferred tax liability attributable to taxable temporary differences.",
        "label": "Deferred Tax Liabilities, Gross",
        "negatedTotalLabel": "Deferred tax liabilities"
       }
      }
     },
     "localname": "DeferredIncomeTaxLiabilities",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DeferredIncomeTaxLiabilitiesNet": {
     "auth_ref": [
      "r334",
      "r351"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetailsCalc2": {
       "order": 2.0,
       "parentTag": "us-gaap_DeferredTaxLiabilities",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences with jurisdictional netting.",
        "label": "Deferred Income Tax Liabilities, Net",
        "negatedTerseLabel": "Noncurrent liabilities"
       }
      }
     },
     "localname": "DeferredIncomeTaxLiabilitiesNet",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DeferredIncomeTaxesAndOtherTaxLiabilitiesNoncurrent": {
     "auth_ref": [],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 3.0,
       "parentTag": "us-gaap_LiabilitiesAndStockholdersEquity",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of deferred tax liability attributable to taxable temporary differences, after deferred tax asset, and other tax liabilities expected to be paid after one year or operating cycle, if longer.",
        "label": "Deferred Income Taxes and Other Tax Liabilities, Noncurrent",
        "terseLabel": "DEFERRED INCOME TAXES AND TAX UNCERTAINTIES"
       }
      }
     },
     "localname": "DeferredIncomeTaxesAndOtherTaxLiabilitiesNoncurrent",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DeferredTaxAssetDomain": {
     "auth_ref": [
      "r350"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Identification of the deferred tax asset for which a valuation reserve exists.",
        "label": "Deferred Tax Asset [Domain]",
        "terseLabel": "Deferred Tax Asset [Domain]"
       }
      }
     },
     "localname": "DeferredTaxAssetDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesChangesInValuationAllowanceDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_DeferredTaxAssetsGross": {
     "auth_ref": [
      "r348"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails": {
       "order": 1.0,
       "parentTag": "us-gaap_DeferredTaxAssetsNet",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.",
        "label": "Deferred Tax Assets, Gross",
        "totalLabel": "Deferred tax assets"
       }
      }
     },
     "localname": "DeferredTaxAssetsGross",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DeferredTaxAssetsLiabilitiesNetAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Deferred Tax Assets, Net, Classification [Abstract]",
        "terseLabel": "The net deferred tax asset (liability) is classified as follows:"
       }
      }
     },
     "localname": "DeferredTaxAssetsLiabilitiesNetAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_DeferredTaxAssetsNet": {
     "auth_ref": [
      "r349"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails": {
       "order": 2.0,
       "parentTag": "us-gaap_DeferredTaxLiabilities",
       "weight": -1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.",
        "label": "Deferred Tax Assets, Net of Valuation Allowance",
        "totalLabel": "Deferred tax assets, net of valuation allowance"
       }
      }
     },
     "localname": "DeferredTaxAssetsNet",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DeferredTaxAssetsNetAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Deferred Tax Assets, Net [Abstract]",
        "terseLabel": "Deferred tax assets:"
       }
      }
     },
     "localname": "DeferredTaxAssetsNetAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsForeign": {
     "auth_ref": [
      "r326",
      "r354",
      "r355"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails": {
       "order": 3.0,
       "parentTag": "us-gaap_DeferredTaxAssetsGross",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount before allocation of valuation allowances of deferred tax asset attributable to deductible foreign operating loss carryforwards.",
        "label": "Deferred Tax Assets, Operating Loss Carryforwards, Foreign",
        "verboseLabel": "Foreign operating loss carryforwards"
       }
      }
     },
     "localname": "DeferredTaxAssetsOperatingLossCarryforwardsForeign",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DeferredTaxAssetsOther": {
     "auth_ref": [
      "r328",
      "r354",
      "r355"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails": {
       "order": 4.0,
       "parentTag": "us-gaap_DeferredTaxAssetsGross",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible temporary differences, classified as other.",
        "label": "Deferred Tax Assets, Other",
        "terseLabel": "Other"
       }
      }
     },
     "localname": "DeferredTaxAssetsOther",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DeferredTaxAssetsTaxCreditCarryforwards": {
     "auth_ref": [
      "r353",
      "r354",
      "r355"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails": {
       "order": 5.0,
       "parentTag": "us-gaap_DeferredTaxAssetsGross",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount, before allocation of a valuation allowances, of deferred tax assets attributable to deductible tax credit carryforwards including, but not limited to, research, foreign, general business, alternative minimum tax, and other deductible tax credit carryforwards.",
        "label": "Deferred Tax Assets, Tax Credit Carryforwards",
        "verboseLabel": "Tax credit carryforward"
       }
      }
     },
     "localname": "DeferredTaxAssetsTaxCreditCarryforwards",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits": {
     "auth_ref": [
      "r326",
      "r354",
      "r355"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails": {
       "order": 2.0,
       "parentTag": "us-gaap_DeferredTaxAssetsGross",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from compensation and benefits costs.",
        "label": "Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits",
        "terseLabel": "Accrued employment-related benefits"
       }
      }
     },
     "localname": "DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities": {
     "auth_ref": [
      "r326",
      "r354",
      "r355"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails": {
       "order": 1.0,
       "parentTag": "us-gaap_DeferredTaxAssetsGross",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from accrued liabilities.",
        "label": "Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Accrued Liabilities",
        "verboseLabel": "Accrued expenses"
       }
      }
     },
     "localname": "DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DeferredTaxAssetsValuationAllowance": {
     "auth_ref": [
      "r350"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails": {
       "order": 2.0,
       "parentTag": "us-gaap_DeferredTaxAssetsNet",
       "weight": -1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.",
        "label": "Deferred Tax Assets, Valuation Allowance",
        "negatedPeriodEndLabel": "Balance at end of period",
        "negatedPeriodStartLabel": "Balance at beginning of period",
        "negatedTerseLabel": "Less valuation allowance"
       }
      }
     },
     "localname": "DeferredTaxAssetsValuationAllowance",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesChangesInValuationAllowanceDetails",
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DeferredTaxLiabilities": {
     "auth_ref": [
      "r334",
      "r351"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      },
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetailsCalc2": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences without jurisdictional netting.",
        "label": "Deferred Tax Liabilities, Net",
        "negatedTotalLabel": "Net deferred tax liability"
       }
      }
     },
     "localname": "DeferredTaxLiabilities",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DeferredTaxLiabilitiesAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Deferred Tax Liabilities, Gross [Abstract]",
        "terseLabel": "Deferred tax liabilities:"
       }
      }
     },
     "localname": "DeferredTaxLiabilitiesAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_DeferredTaxLiabilitiesDeferredExpenseCapitalizedSoftware": {
     "auth_ref": [
      "r327",
      "r354",
      "r355"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails": {
       "order": 3.0,
       "parentTag": "us-gaap_DeferredIncomeTaxLiabilities",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of deferred tax liability attributable to taxable temporary differences from capitalized software.",
        "label": "Deferred Tax Liabilities, Deferred Expense, Capitalized Software",
        "negatedTerseLabel": "Prepaids"
       }
      }
     },
     "localname": "DeferredTaxLiabilitiesDeferredExpenseCapitalizedSoftware",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets": {
     "auth_ref": [
      "r328",
      "r354",
      "r355"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails": {
       "order": 2.0,
       "parentTag": "us-gaap_DeferredIncomeTaxLiabilities",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of deferred tax liability attributable to taxable temporary differences from intangible assets other than goodwill.",
        "label": "Deferred Tax Liabilities, Intangible Assets",
        "negatedTerseLabel": "Intangibles"
       }
      }
     },
     "localname": "DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DeferredTaxLiabilitiesPrepaidExpenses": {
     "auth_ref": [],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails": {
       "order": 4.0,
       "parentTag": "us-gaap_DeferredIncomeTaxLiabilities",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of deferred tax consequences attributable to taxable temporary differences derived from prepaid expenses.",
        "label": "Deferred Tax Liabilities, Prepaid Expenses",
        "negatedLabel": "Other"
       }
      }
     },
     "localname": "DeferredTaxLiabilitiesPrepaidExpenses",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment": {
     "auth_ref": [
      "r328",
      "r354",
      "r355"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails": {
       "order": 1.0,
       "parentTag": "us-gaap_DeferredIncomeTaxLiabilities",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of deferred tax liability attributable to taxable temporary differences from property, plant, and equipment.",
        "label": "Deferred Tax Liabilities, Property, Plant and Equipment",
        "negatedTerseLabel": "Property, buildings and equipment"
       }
      }
     },
     "localname": "DeferredTaxLiabilitiesPropertyPlantAndEquipment",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]",
        "terseLabel": "Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]"
       }
      }
     },
     "localname": "DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax": {
     "auth_ref": [
      "r60",
      "r282"
     ],
     "calculation": {
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails": {
       "order": 2.0,
       "parentTag": "us-gaap_AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax",
       "weight": -1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount, before tax, of accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.",
        "label": "Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax",
        "terseLabel": "Unrecognized gains"
       }
      }
     },
     "localname": "DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax": {
     "auth_ref": [
      "r60",
      "r282"
     ],
     "calculation": {
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails": {
       "order": 1.0,
       "parentTag": "us-gaap_AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount, before tax, of accumulated other comprehensive (income) loss for cost (credit) of benefit change attributable to participants' prior service from plan amendment or plan initiation of defined benefit plan, that has not been recognized in net periodic benefit cost (credit).",
        "label": "Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, Prior Service Cost (Credit), before Tax",
        "negatedTerseLabel": "Prior service credit"
       }
      }
     },
     "localname": "DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets": {
     "auth_ref": [
      "r267",
      "r298"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of increase (decrease) in plan assets of defined benefit plan from actual return (loss) determined by change in fair value of plan assets adjusted for contributions, benefit payments, and other expenses.",
        "label": "Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)",
        "terseLabel": "Actual (losses) returns on plan assets"
       }
      }
     },
     "localname": "DefinedBenefitPlanActualReturnOnPlanAssets",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanActuarialGainLoss": {
     "auth_ref": [
      "r263"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan.",
        "label": "Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)",
        "negatedTerseLabel": "Plan amendment"
       }
      }
     },
     "localname": "DefinedBenefitPlanActuarialGainLoss",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses": {
     "auth_ref": [
      "r279",
      "r296",
      "r298"
     ],
     "calculation": {
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails": {
       "order": 5.0,
       "parentTag": "us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost",
       "weight": -1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of gain (loss) recognized in net periodic benefit (cost) credit of defined benefit plan.",
        "label": "Defined Benefit Plan, Amortization of Gain (Loss)",
        "negatedTerseLabel": "Amortization of unrecognized gains"
       }
      }
     },
     "localname": "DefinedBenefitPlanAmortizationOfGainsLosses",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit": {
     "auth_ref": [
      "r280",
      "r297",
      "r298"
     ],
     "calculation": {
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails": {
       "order": 4.0,
       "parentTag": "us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of prior service cost (credit) recognized in net periodic benefit cost (credit) of defined benefit plan.",
        "label": "Defined Benefit Plan, Amortization of Prior Service Cost (Credit)",
        "terseLabel": "Amortization of prior service credits"
       }
      }
     },
     "localname": "DefinedBenefitPlanAmortizationOfPriorServiceCostCredit",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanAmountsThatWillBeAmortizedFromAccumulatedOtherComprehensiveIncomeLossInNextFiscalYearAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Defined Benefit Plan, Expected Amortization, Next Fiscal Year [Abstract]",
        "terseLabel": "Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]"
       }
      }
     },
     "localname": "DefinedBenefitPlanAmountsThatWillBeAmortizedFromAccumulatedOtherComprehensiveIncomeLossInNextFiscalYearAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate": {
     "auth_ref": [
      "r284"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.",
        "label": "Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate",
        "terseLabel": "Discount rate"
       }
      }
     },
     "localname": "DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate": {
     "auth_ref": [
      "r284"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Weighted average rate for present value of future retirement benefits cash flows, used to determine net periodic benefit cost of defined benefit plan.",
        "label": "Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate",
        "terseLabel": "Discount rate"
       }
      }
     },
     "localname": "DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets": {
     "auth_ref": [
      "r285"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan.",
        "label": "Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets",
        "terseLabel": "Long-term rate of return on plan assets, net of tax"
       }
      }
     },
     "localname": "DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "us-gaap_DefinedBenefitPlanBenefitObligation": {
     "auth_ref": [
      "r259"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.",
        "label": "Defined Benefit Plan, Benefit Obligation",
        "periodEndLabel": "Benefit obligation at end of year",
        "periodStartLabel": "Benefit obligation at beginning of year"
       }
      }
     },
     "localname": "DefinedBenefitPlanBenefitObligation",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid": {
     "auth_ref": [
      "r264",
      "r299"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of payment to participant of defined benefit plan which decreases benefit obligation. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services.",
        "label": "Defined Benefit Plan, Benefit Obligation, Benefits Paid",
        "negatedLabel": "Benefits paid"
       }
      }
     },
     "localname": "DefinedBenefitPlanBenefitObligationBenefitsPaid",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanBenefitObligationContributionsByPlanParticipant": {
     "auth_ref": [
      "r262"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of contributions received by defined benefit plan from participant which increase benefit obligation.",
        "label": "Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant",
        "terseLabel": "Plan participants' contributions"
       }
      }
     },
     "localname": "DefinedBenefitPlanBenefitObligationContributionsByPlanParticipant",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis": {
     "auth_ref": [
      "r272",
      "r273",
      "r287",
      "r298"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by defined benefit plan asset investment.",
        "label": "Defined Benefit Plan, Plan Assets, Category [Axis]",
        "terseLabel": "Defined Benefit Plan by Plan Asset Categories [Axis]"
       }
      }
     },
     "localname": "DefinedBenefitPlanByPlanAssetCategoriesAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.",
        "label": "Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]",
        "terseLabel": "Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]"
       }
      }
     },
     "localname": "DefinedBenefitPlanChangeInBenefitObligationRollForward",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.",
        "label": "Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]",
        "terseLabel": "Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]"
       }
      }
     },
     "localname": "DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_DefinedBenefitPlanDisclosureLineItems": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.",
        "label": "Defined Benefit Plan Disclosure [Line Items]",
        "terseLabel": "Defined Benefit Plan Disclosure [Line Items]"
       }
      }
     },
     "localname": "DefinedBenefitPlanDisclosureLineItems",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsDefinedContributionPlansDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Defined Benefit Plan, Expected Future Benefit Payment [Abstract]",
        "terseLabel": "Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]"
       }
      }
     },
     "localname": "DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter": {
     "auth_ref": [
      "r274"
     ],
     "calculation": {
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails": {
       "order": 6.0,
       "parentTag": "gww_DefinedBenefitPlanExpectedFutureBenefitPaymentTotal",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of benefits for defined benefit plan expected to be paid in five fiscal years after fifth fiscal year following latest fiscal year.",
        "label": "Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter",
        "terseLabel": "2025-2029"
       }
      }
     },
     "localname": "DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths": {
     "auth_ref": [
      "r274"
     ],
     "calculation": {
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails": {
       "order": 1.0,
       "parentTag": "gww_DefinedBenefitPlanExpectedFutureBenefitPaymentTotal",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of benefits for defined benefit plan expected to be paid in next fiscal year following latest fiscal year.",
        "label": "Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months",
        "terseLabel": "2020"
       }
      }
     },
     "localname": "DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive": {
     "auth_ref": [
      "r274"
     ],
     "calculation": {
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails": {
       "order": 5.0,
       "parentTag": "gww_DefinedBenefitPlanExpectedFutureBenefitPaymentTotal",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of benefits for defined benefit plan expected to be paid in fifth fiscal year following latest fiscal year.",
        "label": "Defined Benefit Plan, Expected Future Benefit Payment, Year Five",
        "terseLabel": "2024"
       }
      }
     },
     "localname": "DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour": {
     "auth_ref": [
      "r274"
     ],
     "calculation": {
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails": {
       "order": 4.0,
       "parentTag": "gww_DefinedBenefitPlanExpectedFutureBenefitPaymentTotal",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of benefits for defined benefit plan expected to be paid in fourth fiscal year following latest fiscal year.",
        "label": "Defined Benefit Plan, Expected Future Benefit Payment, Year Four",
        "terseLabel": "2023"
       }
      }
     },
     "localname": "DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree": {
     "auth_ref": [
      "r274"
     ],
     "calculation": {
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails": {
       "order": 3.0,
       "parentTag": "gww_DefinedBenefitPlanExpectedFutureBenefitPaymentTotal",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of benefits for defined benefit plan expected to be paid in third fiscal year following latest fiscal year.",
        "label": "Defined Benefit Plan, Expected Future Benefit Payment, Year Three",
        "terseLabel": "2022"
       }
      }
     },
     "localname": "DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo": {
     "auth_ref": [
      "r274"
     ],
     "calculation": {
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails": {
       "order": 2.0,
       "parentTag": "gww_DefinedBenefitPlanExpectedFutureBenefitPaymentTotal",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of benefits for defined benefit plan expected to be paid in second fiscal year following latest fiscal year.",
        "label": "Defined Benefit Plan, Expected Future Benefit Payment, Year Two",
        "terseLabel": "2021"
       }
      }
     },
     "localname": "DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets": {
     "auth_ref": [
      "r278",
      "r295",
      "r298"
     ],
     "calculation": {
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails": {
       "order": 3.0,
       "parentTag": "us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost",
       "weight": -1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of expected return (loss) recognized in net periodic benefit (cost) credit, calculated based on expected long-term rate of return and market-related value of plan assets of defined benefit plan.",
        "label": "Defined Benefit Plan, Expected Return (Loss) on Plan Assets",
        "negatedLabel": "Expected return on assets"
       }
      }
     },
     "localname": "DefinedBenefitPlanExpectedReturnOnPlanAssets",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanFairValueOfPlanAssets": {
     "auth_ref": [
      "r266",
      "r272",
      "r273",
      "r298"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.",
        "label": "Defined Benefit Plan, Plan Assets, Amount",
        "periodEndLabel": "Plan assets available for benefits at end of year",
        "periodStartLabel": "Plan assets available for benefits at beginning of year"
       }
      }
     },
     "localname": "DefinedBenefitPlanFairValueOfPlanAssets",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanInterestCost": {
     "auth_ref": [
      "r261",
      "r277",
      "r294",
      "r298"
     ],
     "calculation": {
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails": {
       "order": 2.0,
       "parentTag": "us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of cost recognized for passage of time related to defined benefit plan.",
        "label": "Defined Benefit Plan, Interest Cost",
        "terseLabel": "Interest cost"
       }
      }
     },
     "localname": "DefinedBenefitPlanInterestCost",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost": {
     "auth_ref": [
      "r275",
      "r292",
      "r298"
     ],
     "calculation": {
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of net periodic benefit cost (credit) for defined benefit plan.",
        "label": "Defined Benefit Plan, Net Periodic Benefit Cost (Credit)",
        "totalLabel": "Net periodic (benefits) costs"
       }
      }
     },
     "localname": "DefinedBenefitPlanNetPeriodicBenefitCost",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanOtherCosts": {
     "auth_ref": [],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of defined benefit plan cost (credit), classified as other.",
        "label": "Defined Benefit Plan, Other Cost (Credit)",
        "terseLabel": "Prescription drug rebates"
       }
      }
     },
     "localname": "DefinedBenefitPlanOtherCosts",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanPlanAmendments": {
     "auth_ref": [
      "r265"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of increase (decrease) in benefit obligation of defined benefit plan from change in terms of existing plan or initiation of new plan.",
        "label": "Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment",
        "terseLabel": "Actuarial (gains)"
       }
      }
     },
     "localname": "DefinedBenefitPlanPlanAmendments",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid": {
     "auth_ref": [
      "r269",
      "r299"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of payment to participant under defined benefit plan which decreases plan assets. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services.",
        "label": "Defined Benefit Plan, Plan Assets, Benefits Paid",
        "negatedTerseLabel": "Benefits paid"
       }
      }
     },
     "localname": "DefinedBenefitPlanPlanAssetsBenefitsPaid",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanPlanAssetsContributionsByPlanParticipant": {
     "auth_ref": [
      "r268"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of contributions received by defined benefit plan from participant which increases plan assets.",
        "label": "Defined Benefit Plan, Plan Assets, Contributions by Plan Participant",
        "terseLabel": "Plan participants' contributions"
       }
      }
     },
     "localname": "DefinedBenefitPlanPlanAssetsContributionsByPlanParticipant",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanServiceCost": {
     "auth_ref": [
      "r260",
      "r276",
      "r293",
      "r298"
     ],
     "calculation": {
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails": {
       "order": 1.0,
       "parentTag": "us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.",
        "label": "Defined Benefit Plan, Service Cost",
        "terseLabel": "Service cost"
       }
      }
     },
     "localname": "DefinedBenefitPlanServiceCost",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DefinedBenefitPlanUltimateHealthCareCostTrendRate1": {
     "auth_ref": [
      "r286"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Ultimate trend rate for health care cost for defined benefit postretirement plan.",
        "label": "Defined Benefit Plan, Ultimate Health Care Cost Trend Rate",
        "terseLabel": "Ultimate healthcare cost trend rate"
       }
      }
     },
     "localname": "DefinedBenefitPlanUltimateHealthCareCostTrendRate1",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]",
        "terseLabel": "Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]"
       }
      }
     },
     "localname": "DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]",
        "terseLabel": "Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]"
       }
      }
     },
     "localname": "DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_DefinedBenefitPlanYearHealthCareCostTrendRateReachesUltimateTrendRate": {
     "auth_ref": [
      "r286"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Year ultimate health care cost trend rate is expected to be reached, in CCYY format.",
        "label": "Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate",
        "terseLabel": "Year ultimate healthcare cost trend rate reached"
       }
      }
     },
     "localname": "DefinedBenefitPlanYearHealthCareCostTrendRateReachesUltimateTrendRate",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "gYearListItemType"
    },
    "us-gaap_DefinedContributionPlanCostRecognized": {
     "auth_ref": [
      "r300"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of cost for defined contribution plan.",
        "label": "Defined Contribution Plan, Cost",
        "terseLabel": "Defined Contribution Plan, Cost",
        "verboseLabel": "Defined contribution plans, expense"
       }
      }
     },
     "localname": "DefinedContributionPlanCostRecognized",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsDefinedContributionPlansDetails",
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_Depreciation": {
     "auth_ref": [
      "r102",
      "r206"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.",
        "label": "Depreciation",
        "terseLabel": "Depreciation"
       }
      }
     },
     "localname": "Depreciation",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DepreciationAndAmortization": {
     "auth_ref": [
      "r102",
      "r206"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 4.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production.",
        "label": "Depreciation, Depletion and Amortization, Nonproduction",
        "terseLabel": "Depreciation and amortization"
       }
      }
     },
     "localname": "DepreciationAndAmortization",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DepreciationDepletionAndAmortization": {
     "auth_ref": [
      "r102",
      "r151"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.",
        "label": "Depreciation, Depletion and Amortization",
        "terseLabel": "Depreciation and amortization"
       }
      }
     },
     "localname": "DepreciationDepletionAndAmortization",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DisaggregationOfRevenueLineItems": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.",
        "label": "Disaggregation of Revenue [Line Items]",
        "terseLabel": "Disaggregation of Revenue [Line Items]"
       }
      }
     },
     "localname": "DisaggregationOfRevenueLineItems",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails",
      "http://www.grainger.com/role/RevenueTables"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_DisaggregationOfRevenueTable": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of information about disaggregation of revenue into categories depicting how nature, amount, timing, and uncertainty of revenue and cash flows are affected by economic factor.",
        "label": "Disaggregation of Revenue [Table]",
        "terseLabel": "Disaggregation of Revenue [Table]"
       }
      }
     },
     "localname": "DisaggregationOfRevenueTable",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails",
      "http://www.grainger.com/role/RevenueTables"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_DisaggregationOfRevenueTableTextBlock": {
     "auth_ref": [
      "r243"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of disaggregation of revenue into categories depicting how nature, amount, timing, and uncertainty of revenue and cash flows are affected by economic factor.",
        "label": "Disaggregation of Revenue [Table Text Block]",
        "terseLabel": "Disaggregation of Revenue"
       }
      }
     },
     "localname": "DisaggregationOfRevenueTableTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RevenueTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock": {
     "auth_ref": [
      "r323"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The entire disclosure for share-based payment arrangement.",
        "label": "Share-based Payment Arrangement [Text Block]",
        "terseLabel": "STOCK INCENTIVE PLANS"
       }
      }
     },
     "localname": "DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlans"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_DividendsCommonStockCash": {
     "auth_ref": [
      "r238"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of paid and unpaid common stock dividends declared with the form of settlement in cash.",
        "label": "Dividends, Common Stock, Cash",
        "negatedTerseLabel": "Cash dividends paid"
       }
      }
     },
     "localname": "DividendsCommonStockCash",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfShareholdersEquity"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_DomesticLineOfCreditMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Contractual arrangement with a lender under which borrowings can be made up to a specific amount at any point in time, and under which borrowings outstanding may be either short-term or long-term, depending upon the particulars, inside the reporting entity's home country.",
        "label": "Domestic Line of Credit [Member]",
        "terseLabel": "Domestic Line of Credit [Member]"
       }
      }
     },
     "localname": "DomesticLineOfCreditMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ShortTermDebtDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_EarningsPerShareAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Earnings Per Share [Abstract]",
        "terseLabel": "Earnings per share:"
       }
      }
     },
     "localname": "EarningsPerShareAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_EarningsPerShareBasic": {
     "auth_ref": [
      "r74",
      "r123",
      "r126",
      "r127",
      "r128",
      "r129",
      "r131",
      "r439",
      "r458"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.",
        "label": "Earnings Per Share, Basic",
        "terseLabel": "Basic (in dollars per share)",
        "verboseLabel": "Earnings per share - basic (in dollars per share)"
       }
      }
     },
     "localname": "EarningsPerShareBasic",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings",
      "http://www.grainger.com/role/SelectedQuarterlyFinancialDataUnauditedDetails"
     ],
     "xbrltype": "perShareItemType"
    },
    "us-gaap_EarningsPerShareDiluted": {
     "auth_ref": [
      "r74",
      "r123",
      "r126",
      "r127",
      "r128",
      "r129",
      "r131",
      "r439",
      "r458"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.",
        "label": "Earnings Per Share, Diluted",
        "terseLabel": "Diluted (in dollars per share)",
        "verboseLabel": "Earnings per share - diluted (in dollars per share)"
       }
      }
     },
     "localname": "EarningsPerShareDiluted",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings",
      "http://www.grainger.com/role/SelectedQuarterlyFinancialDataUnauditedDetails"
     ],
     "xbrltype": "perShareItemType"
    },
    "us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents": {
     "auth_ref": [
      "r394"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 4.0,
       "parentTag": "us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of increase (decrease) from the effect of exchange rate changes on cash and cash equivalent balances held in foreign currencies.",
        "label": "Effect of Exchange Rate on Cash and Cash Equivalents",
        "terseLabel": "Exchange rate effect on cash and cash equivalents"
       }
      }
     },
     "localname": "EffectOfExchangeRateOnCashAndCashEquivalents",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_EffectiveIncomeTaxRateContinuingOperations": {
     "auth_ref": [
      "r117",
      "r336",
      "r337"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.",
        "label": "Effective Income Tax Rate Reconciliation, Percent",
        "terseLabel": "Effective tax rate"
       }
      }
     },
     "localname": "EffectiveIncomeTaxRateContinuingOperations",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseWithFederalIncomeTaxesAtStatutoryRateDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "us-gaap_EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Amount": {
     "auth_ref": [
      "r336"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseWithFederalIncomeTaxesAtStatutoryRateDetails": {
       "order": 5.0,
       "parentTag": "us-gaap_IncomeTaxExpenseBenefit",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of reported income tax expense (benefit) in excess of (less than) expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operations, attributable to Tax Cuts and Jobs Act.",
        "label": "Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act, Amount",
        "terseLabel": "U.S. tax legislation impact"
       }
      }
     },
     "localname": "EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Amount",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseWithFederalIncomeTaxesAtStatutoryRateDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_EmployeeRelatedLiabilitiesCurrent": {
     "auth_ref": [
      "r41"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 4.0,
       "parentTag": "us-gaap_LiabilitiesCurrent",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Total of the carrying values as of the balance sheet date of obligations incurred through that date and payable for obligations related to services received from employees, such as accrued salaries and bonuses, payroll taxes and fringe benefits. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).",
        "label": "Employee-related Liabilities, Current",
        "terseLabel": "Accrued compensation and benefits"
       }
      }
     },
     "localname": "EmployeeRelatedLiabilitiesCurrent",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized": {
     "auth_ref": [
      "r318"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of cost not yet recognized for nonvested award under share-based payment arrangement.",
        "label": "Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount",
        "terseLabel": "Unrecognized compensation"
       }
      }
     },
     "localname": "EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansDetails",
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails",
      "http://www.grainger.com/role/StockIncentivePlansStockOptionsOutstandingAndExercisableDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1": {
     "auth_ref": [
      "r318"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.",
        "label": "Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition",
        "terseLabel": "Weighted average period to recognize (in years)"
       }
      }
     },
     "localname": "EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansDetails",
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails",
      "http://www.grainger.com/role/StockIncentivePlansStockOptionsOutstandingAndExercisableDetails"
     ],
     "xbrltype": "durationItemType"
    },
    "us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense": {
     "auth_ref": [
      "r317"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of tax benefit for recognition of expense of award under share-based payment arrangement.",
        "label": "Share-based Payment Arrangement, Expense, Tax Benefit",
        "terseLabel": "Income tax benefits recognized in earnings for stock-based compensation expense"
       }
      }
     },
     "localname": "EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_EmployeeStockOptionMember": {
     "auth_ref": [
      "r316"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Share-based payment arrangement granting right, subject to vesting and other restrictions, to purchase or sell certain number of shares at predetermined price for specified period of time.",
        "label": "Share-based Payment Arrangement, Option [Member]",
        "terseLabel": "Stock Options [Member]"
       }
      }
     },
     "localname": "EmployeeStockOptionMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansDetails",
      "http://www.grainger.com/role/StockIncentivePlansStockOptionsOutstandingAndExercisableDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_EquityComponentDomain": {
     "auth_ref": [
      "r233"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Components of equity are the parts of the total Equity balance including that which is allocated to common, preferred, treasury stock, retained earnings, etc.",
        "label": "Equity Component [Domain]",
        "terseLabel": "Equity Component [Domain]"
       }
      }
     },
     "localname": "EquityComponentDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails",
      "http://www.grainger.com/role/CapitalStockDetails",
      "http://www.grainger.com/role/ConsolidatedStatementsOfShareholdersEquity",
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities": {
     "auth_ref": [
      "r322"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 6.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of cash inflow from realized tax benefit related to deductible compensation cost reported on the entity's tax return for equity instruments in excess of the compensation cost for those instruments recognized for financial reporting purposes.",
        "label": "Excess Tax Benefit from Share-based Compensation, Financing Activities",
        "terseLabel": "Payments for employee taxes withheld from stock awards"
       }
      }
     },
     "localname": "ExcessTaxBenefitFromShareBasedCompensationFinancingActivities",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain": {
     "auth_ref": [
      "r391"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Class of asset.",
        "label": "Asset Class [Domain]",
        "terseLabel": "Intangible Assets [Domain]"
       }
      }
     },
     "localname": "FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_FairValueByAssetClassAxis": {
     "auth_ref": [
      "r389",
      "r392"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by class of asset.",
        "label": "Asset Class [Axis]",
        "terseLabel": "Intangible Assets [Axis]"
       }
      }
     },
     "localname": "FairValueByAssetClassAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_FairValueByFairValueHierarchyLevelAxis": {
     "auth_ref": [
      "r272",
      "r273",
      "r298",
      "r390",
      "r423"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by level within fair value hierarchy and fair value measured at net asset value per share as practical expedient.",
        "label": "Fair Value Hierarchy and NAV [Axis]",
        "terseLabel": "Defined Benefit Plan, Fair Value of Plan Assets by Measurement [Axis]"
       }
      }
     },
     "localname": "FairValueByFairValueHierarchyLevelAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_FairValueInputsLevel1Member": {
     "auth_ref": [
      "r272",
      "r273",
      "r298",
      "r390",
      "r424"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Quoted prices in active markets for identical assets or liabilities that the reporting entity can access at the measurement date.",
        "label": "Fair Value, Inputs, Level 1 [Member]",
        "terseLabel": "Fair Value, Inputs, Level 1 [Member]"
       }
      }
     },
     "localname": "FairValueInputsLevel1Member",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_FairValueMeasurementsFairValueHierarchyDomain": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Categories used to prioritize the inputs to valuation techniques to measure fair value.",
        "label": "Fair Value Hierarchy and NAV [Domain]",
        "terseLabel": "Fair Value Plan Asset Measurement [Domain]"
       }
      }
     },
     "localname": "FairValueMeasurementsFairValueHierarchyDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_FiniteLivedIntangibleAssetUsefulLife": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.",
        "label": "Finite-Lived Intangible Asset, Useful Life",
        "terseLabel": "Finite-lived intangible assets, useful life"
       }
      }
     },
     "localname": "FiniteLivedIntangibleAssetUsefulLife",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails"
     ],
     "xbrltype": "durationItemType"
    },
    "us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization": {
     "auth_ref": [
      "r196"
     ],
     "calculation": {
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails": {
       "order": 2.0,
       "parentTag": "us-gaap_FiniteLivedIntangibleAssetsNet",
       "weight": -1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.",
        "label": "Finite-Lived Intangible Assets, Accumulated Amortization",
        "terseLabel": "Finite-lived intangible assets, accumulated amortization"
       }
      }
     },
     "localname": "FiniteLivedIntangibleAssetsAccumulatedAmortization",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive": {
     "auth_ref": [],
     "calculation": {
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsEstimatedAmortizationExpenseDetails": {
       "order": 6.0,
       "parentTag": "us-gaap_FiniteLivedIntangibleAssetsNet",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.",
        "label": "Finite-Lived Intangible Assets, Amortization Expense, after Year Five",
        "terseLabel": "Thereafter"
       }
      }
     },
     "localname": "FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsEstimatedAmortizationExpenseDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths": {
     "auth_ref": [
      "r198"
     ],
     "calculation": {
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsEstimatedAmortizationExpenseDetails": {
       "order": 1.0,
       "parentTag": "us-gaap_FiniteLivedIntangibleAssetsNet",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.",
        "label": "Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months",
        "terseLabel": "2020"
       }
      }
     },
     "localname": "FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsEstimatedAmortizationExpenseDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive": {
     "auth_ref": [
      "r198"
     ],
     "calculation": {
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsEstimatedAmortizationExpenseDetails": {
       "order": 5.0,
       "parentTag": "us-gaap_FiniteLivedIntangibleAssetsNet",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.",
        "label": "Finite-Lived Intangible Assets, Amortization Expense, Year Five",
        "terseLabel": "2024"
       }
      }
     },
     "localname": "FiniteLivedIntangibleAssetsAmortizationExpenseYearFive",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsEstimatedAmortizationExpenseDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour": {
     "auth_ref": [
      "r198"
     ],
     "calculation": {
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsEstimatedAmortizationExpenseDetails": {
       "order": 4.0,
       "parentTag": "us-gaap_FiniteLivedIntangibleAssetsNet",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.",
        "label": "Finite-Lived Intangible Assets, Amortization Expense, Year Four",
        "terseLabel": "2023"
       }
      }
     },
     "localname": "FiniteLivedIntangibleAssetsAmortizationExpenseYearFour",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsEstimatedAmortizationExpenseDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree": {
     "auth_ref": [
      "r198"
     ],
     "calculation": {
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsEstimatedAmortizationExpenseDetails": {
       "order": 3.0,
       "parentTag": "us-gaap_FiniteLivedIntangibleAssetsNet",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.",
        "label": "Finite-Lived Intangible Assets, Amortization Expense, Year Three",
        "terseLabel": "2022"
       }
      }
     },
     "localname": "FiniteLivedIntangibleAssetsAmortizationExpenseYearThree",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsEstimatedAmortizationExpenseDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo": {
     "auth_ref": [
      "r198"
     ],
     "calculation": {
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsEstimatedAmortizationExpenseDetails": {
       "order": 2.0,
       "parentTag": "us-gaap_FiniteLivedIntangibleAssetsNet",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.",
        "label": "Finite-Lived Intangible Assets, Amortization Expense, Year Two",
        "terseLabel": "2021"
       }
      }
     },
     "localname": "FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsEstimatedAmortizationExpenseDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_FiniteLivedIntangibleAssetsGross": {
     "auth_ref": [
      "r196",
      "r425"
     ],
     "calculation": {
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails": {
       "order": 2.0,
       "parentTag": "us-gaap_IntangibleAssetsGrossExcludingGoodwill",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.",
        "label": "Finite-Lived Intangible Assets, Gross",
        "terseLabel": "Finite-lived intangible assets, gross"
       }
      }
     },
     "localname": "FiniteLivedIntangibleAssetsGross",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_FiniteLivedIntangibleAssetsNet": {
     "auth_ref": [
      "r196"
     ],
     "calculation": {
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsEstimatedAmortizationExpenseDetails": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      },
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails": {
       "order": 2.0,
       "parentTag": "us-gaap_IntangibleAssetsNetExcludingGoodwill",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.",
        "label": "Finite-Lived Intangible Assets, Net",
        "totalLabel": "Total"
       }
      }
     },
     "localname": "FiniteLivedIntangibleAssetsNet",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsEstimatedAmortizationExpenseDetails",
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock": {
     "auth_ref": [
      "r108",
      "r393",
      "r398"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of accounting policy for (1) transactions denominated in a currency other than the reporting enterprise's functional currency, (2) translating foreign currency financial statements that are incorporated into the financial statements of the reporting enterprise by consolidation, combination, or the equity method of accounting, and (3) remeasurement of the financial statements of a foreign reporting enterprise in a hyperinflationary economy.",
        "label": "Foreign Currency Transactions and Translations Policy [Policy Text Block]",
        "terseLabel": "FOREIGN CURRENCY TRANSLATION"
       }
      }
     },
     "localname": "ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_GainLossOnDispositionOfAssets": {
     "auth_ref": [
      "r102",
      "r205",
      "r210"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 6.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities",
       "weight": -1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of gain (loss) on sale or disposal of property, plant and equipment assets, excluding oil and gas property and timber property.",
        "label": "Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property",
        "negatedTerseLabel": "Net (gains) losses from sales of assets and business divestitures"
       }
      }
     },
     "localname": "GainLossOnDispositionOfAssets",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_Goodwill": {
     "auth_ref": [
      "r180",
      "r182"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 1.0,
       "parentTag": "us-gaap_Assets",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.",
        "label": "Goodwill",
        "periodEndLabel": "Goodwill, ending balance",
        "periodStartLabel": "Goodwill, beginning balance",
        "terseLabel": "GOODWILL"
       }
      }
     },
     "localname": "Goodwill",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets",
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsAdditionalInformationDetails",
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsBalancesAndChangesInCarryingAmountsOfGoodwillDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_GoodwillAndIntangibleAssetImpairment": {
     "auth_ref": [],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 5.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Total loss recognized during the period from the impairment of goodwill plus the loss recognized in the period resulting from the impairment of the carrying amount of intangible assets, other than goodwill.",
        "label": "Goodwill and Intangible Asset Impairment",
        "terseLabel": "Impairment of goodwill, intangible and other assets"
       }
      }
     },
     "localname": "GoodwillAndIntangibleAssetImpairment",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows",
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsAdditionalInformationDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock": {
     "auth_ref": [
      "r203"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The entire disclosure for goodwill and intangible assets.",
        "label": "Goodwill and Intangible Assets Disclosure [Text Block]",
        "terseLabel": "GOODWILL AND OTHER INTANGIBLE ASSETS"
       }
      }
     },
     "localname": "GoodwillAndIntangibleAssetsDisclosureTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssets"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_GoodwillAndIntangibleAssetsPolicyTextBlock": {
     "auth_ref": [
      "r108",
      "r187",
      "r193"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of accounting policy for goodwill and intangible assets. This accounting policy also may address how an entity assesses and measures impairment of goodwill and intangible assets.",
        "label": "Goodwill and Intangible Assets, Policy [Policy Text Block]",
        "terseLabel": "GOODWILL AND OTHER INTANGIBLES ASSETS"
       }
      }
     },
     "localname": "GoodwillAndIntangibleAssetsPolicyTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_GoodwillForeignCurrencyTranslationGainLoss": {
     "auth_ref": [
      "r185"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.",
        "label": "Goodwill, Foreign Currency Translation Gain (Loss)",
        "terseLabel": "Translation"
       }
      }
     },
     "localname": "GoodwillForeignCurrencyTranslationGainLoss",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsBalancesAndChangesInCarryingAmountsOfGoodwillDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_GoodwillImpairedAccumulatedImpairmentLoss": {
     "auth_ref": [
      "r183",
      "r186"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.",
        "label": "Goodwill, Impaired, Accumulated Impairment Loss",
        "periodEndLabel": "Cumulative goodwill impairment charges, December 31, 2019 (1)",
        "periodStartLabel": "Cumulative goodwill impairment charges, January 1, 2019 (1)"
       }
      }
     },
     "localname": "GoodwillImpairedAccumulatedImpairmentLoss",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsBalancesAndChangesInCarryingAmountsOfGoodwillDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_GoodwillImpairedAccumulatedImpairmentLossAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Goodwill, Impaired, Accumulated Impairment Loss [Abstract]",
        "terseLabel": "Goodwill, Impaired, Accumulated Impairment Loss [Abstract]"
       }
      }
     },
     "localname": "GoodwillImpairedAccumulatedImpairmentLossAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsBalancesAndChangesInCarryingAmountsOfGoodwillDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_GoodwillImpairmentLoss": {
     "auth_ref": [
      "r102",
      "r181",
      "r184",
      "r188"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.",
        "label": "Goodwill, Impairment Loss",
        "negatedTerseLabel": "Impairment"
       }
      }
     },
     "localname": "GoodwillImpairmentLoss",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsBalancesAndChangesInCarryingAmountsOfGoodwillDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_GoodwillLineItems": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.",
        "label": "Goodwill [Line Items]",
        "terseLabel": "Goodwill [Line Items]"
       }
      }
     },
     "localname": "GoodwillLineItems",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsBalancesAndChangesInCarryingAmountsOfGoodwillDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_GoodwillRollForward": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.",
        "label": "Goodwill [Roll Forward]",
        "terseLabel": "Goodwill [Roll Forward]"
       }
      }
     },
     "localname": "GoodwillRollForward",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsBalancesAndChangesInCarryingAmountsOfGoodwillDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_GrossProfit": {
     "auth_ref": [
      "r76"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings": {
       "order": 1.0,
       "parentTag": "us-gaap_OperatingIncomeLoss",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.",
        "label": "Gross Profit",
        "terseLabel": "Gross profit",
        "totalLabel": "Gross profit"
       }
      }
     },
     "localname": "GrossProfit",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings",
      "http://www.grainger.com/role/SelectedQuarterlyFinancialDataUnauditedDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_ImpairmentOfIntangibleAssetsExcludingGoodwill": {
     "auth_ref": [
      "r102",
      "r200"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of an intangible asset (excluding goodwill) to fair value.",
        "label": "Impairment of Intangible Assets (Excluding Goodwill)",
        "terseLabel": "Impairment of Intangible Assets (Excluding Goodwill)"
       }
      }
     },
     "localname": "ImpairmentOfIntangibleAssetsExcludingGoodwill",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsAdditionalInformationDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock": {
     "auth_ref": [
      "r108",
      "r204",
      "r213"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of accounting policy for recognizing and measuring the impairment of long-lived assets. An entity also may disclose its accounting policy for long-lived assets to be sold. This policy excludes goodwill and intangible assets.",
        "label": "Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]",
        "terseLabel": "LONG-LIVED ASSETS"
       }
      }
     },
     "localname": "ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic": {
     "auth_ref": [
      "r116"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesNetEarningsBeforeIncomeTaxesByGeographicalAreaDetails": {
       "order": 1.0,
       "parentTag": "us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The portion of earnings or loss from continuing operations before income taxes that is attributable to domestic operations.",
        "label": "Income (Loss) from Continuing Operations before Income Taxes, Domestic",
        "terseLabel": "U.S."
       }
      }
     },
     "localname": "IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesNetEarningsBeforeIncomeTaxesByGeographicalAreaDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest": {
     "auth_ref": [
      "r72",
      "r123",
      "r426",
      "r437",
      "r459"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings": {
       "order": 2.0,
       "parentTag": "us-gaap_ProfitLoss",
       "weight": 1.0
      },
      "http://www.grainger.com/role/IncomeTaxesNetEarningsBeforeIncomeTaxesByGeographicalAreaDetails": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.",
        "label": "Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest",
        "totalLabel": "Earnings before income taxes"
       }
      }
     },
     "localname": "IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings",
      "http://www.grainger.com/role/IncomeTaxesNetEarningsBeforeIncomeTaxesByGeographicalAreaDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign": {
     "auth_ref": [
      "r116"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesNetEarningsBeforeIncomeTaxesByGeographicalAreaDetails": {
       "order": 2.0,
       "parentTag": "us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The portion of earnings or loss from continuing operations before income taxes that is attributable to foreign operations, which is defined as Income or Loss generated from operations located outside the entity's country of domicile.",
        "label": "Income (Loss) from Continuing Operations before Income Taxes, Foreign",
        "terseLabel": "Foreign"
       }
      }
     },
     "localname": "IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesNetEarningsBeforeIncomeTaxesByGeographicalAreaDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest [Abstract]",
        "terseLabel": "Net earnings before income taxes by geographical area"
       }
      }
     },
     "localname": "IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesNetEarningsBeforeIncomeTaxesByGeographicalAreaDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_IncomeStatementAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Income Statement [Abstract]"
       }
      }
     },
     "localname": "IncomeStatementAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "xbrltype": "stringItemType"
    },
    "us-gaap_IncomeStatementLocationAxis": {
     "auth_ref": [
      "r211"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by location in the income statement.",
        "label": "Income Statement Location [Axis]",
        "terseLabel": "Income Statement Location [Axis]"
       }
      }
     },
     "localname": "IncomeStatementLocationAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_IncomeStatementLocationDomain": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Location in the income statement.",
        "label": "Income Statement Location [Domain]",
        "terseLabel": "Income Statement Location [Domain]"
       }
      }
     },
     "localname": "IncomeStatementLocationDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_IncomeTaxDisclosureAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Income Tax Disclosure [Abstract]"
       }
      }
     },
     "localname": "IncomeTaxDisclosureAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "xbrltype": "stringItemType"
    },
    "us-gaap_IncomeTaxDisclosureTextBlock": {
     "auth_ref": [
      "r364"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.",
        "label": "Income Tax Disclosure [Text Block]",
        "terseLabel": "INCOME TAXES"
       }
      }
     },
     "localname": "IncomeTaxDisclosureTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxes"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_IncomeTaxExpenseBenefit": {
     "auth_ref": [
      "r113",
      "r152",
      "r361"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings": {
       "order": 1.0,
       "parentTag": "us-gaap_ProfitLoss",
       "weight": -1.0
      },
      "http://www.grainger.com/role/IncomeTaxesDetails": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      },
      "http://www.grainger.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseWithFederalIncomeTaxesAtStatutoryRateDetails": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.",
        "label": "Income Tax Expense (Benefit)",
        "terseLabel": "Income taxes",
        "totalLabel": "Income tax expense"
       }
      }
     },
     "localname": "IncomeTaxExpenseBenefit",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings",
      "http://www.grainger.com/role/IncomeTaxesDetails",
      "http://www.grainger.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseWithFederalIncomeTaxesAtStatutoryRateDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Effective Income Tax Rate Reconciliation, Amount [Abstract]",
        "terseLabel": "Reconciliation of income tax expense with federal income taxes at the statutory rate"
       }
      }
     },
     "localname": "IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseWithFederalIncomeTaxesAtStatutoryRateDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_IncomeTaxPolicyTextBlock": {
     "auth_ref": [
      "r70",
      "r108",
      "r332",
      "r333",
      "r345",
      "r346",
      "r352",
      "r362",
      "r469"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of accounting policy for income taxes, which may include its accounting policies for recognizing and measuring deferred tax assets and liabilities and related valuation allowances, recognizing investment tax credits, operating loss carryforwards, tax credit carryforwards, and other carryforwards, methodologies for determining its effective income tax rate and the characterization of interest and penalties in the financial statements.",
        "label": "Income Tax, Policy [Policy Text Block]",
        "terseLabel": "INCOME TAXES"
       }
      }
     },
     "localname": "IncomeTaxPolicyTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_IncomeTaxReconciliationForeignIncomeTaxRateDifferential": {
     "auth_ref": [
      "r111",
      "r336",
      "r337"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseWithFederalIncomeTaxesAtStatutoryRateDetails": {
       "order": 3.0,
       "parentTag": "us-gaap_IncomeTaxExpenseBenefit",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to foreign income tax expense (benefit).",
        "label": "Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount",
        "terseLabel": "Foreign rate difference"
       }
      }
     },
     "localname": "IncomeTaxReconciliationForeignIncomeTaxRateDifferential",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseWithFederalIncomeTaxesAtStatutoryRateDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate": {
     "auth_ref": [
      "r112",
      "r336",
      "r337"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseWithFederalIncomeTaxesAtStatutoryRateDetails": {
       "order": 1.0,
       "parentTag": "us-gaap_IncomeTaxExpenseBenefit",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.",
        "label": "Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount",
        "terseLabel": "Federal income tax"
       }
      }
     },
     "localname": "IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseWithFederalIncomeTaxesAtStatutoryRateDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_IncomeTaxReconciliationNondeductibleExpenseImpairmentLosses": {
     "auth_ref": [
      "r336",
      "r337"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseWithFederalIncomeTaxesAtStatutoryRateDetails": {
       "order": 6.0,
       "parentTag": "us-gaap_IncomeTaxExpenseBenefit",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to nondeductible impairment loss.",
        "label": "Effective Income Tax Rate Reconciliation, Nondeductible Expense, Impairment Losses, Amount",
        "terseLabel": "Goodwill impairment"
       }
      }
     },
     "localname": "IncomeTaxReconciliationNondeductibleExpenseImpairmentLosses",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseWithFederalIncomeTaxesAtStatutoryRateDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost": {
     "auth_ref": [
      "r336",
      "r337"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseWithFederalIncomeTaxesAtStatutoryRateDetails": {
       "order": 7.0,
       "parentTag": "us-gaap_IncomeTaxExpenseBenefit",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of reported income tax expense (benefit) in excess of (less than) expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operation, attributable to nondeductible expense for award under share-based payment arrangement. Includes, but is not limited to, expense determined to be nondeductible upon grant or after for award under share-based payment arrangement.",
        "label": "Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Payment Arrangement, Amount",
        "terseLabel": "Excess tax benefits from stock-based compensation"
       }
      }
     },
     "localname": "IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseWithFederalIncomeTaxesAtStatutoryRateDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_IncomeTaxReconciliationOtherAdjustments": {
     "auth_ref": [
      "r336"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseWithFederalIncomeTaxesAtStatutoryRateDetails": {
       "order": 4.0,
       "parentTag": "us-gaap_IncomeTaxExpenseBenefit",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to other adjustments.",
        "label": "Effective Income Tax Rate Reconciliation, Other Adjustments, Amount",
        "terseLabel": "Other - net"
       }
      }
     },
     "localname": "IncomeTaxReconciliationOtherAdjustments",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseWithFederalIncomeTaxesAtStatutoryRateDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes": {
     "auth_ref": [
      "r112",
      "r336",
      "r337"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseWithFederalIncomeTaxesAtStatutoryRateDetails": {
       "order": 2.0,
       "parentTag": "us-gaap_IncomeTaxExpenseBenefit",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to state and local income tax expense (benefit).",
        "label": "Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount",
        "terseLabel": "State income taxes, net of federal income tax benefit"
       }
      }
     },
     "localname": "IncomeTaxReconciliationStateAndLocalIncomeTaxes",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseWithFederalIncomeTaxesAtStatutoryRateDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_IncomeTaxReconciliationTaxCredits": {
     "auth_ref": [
      "r336",
      "r337"
     ],
     "calculation": {
      "http://www.grainger.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseWithFederalIncomeTaxesAtStatutoryRateDetails": {
       "order": 8.0,
       "parentTag": "us-gaap_IncomeTaxExpenseBenefit",
       "weight": -1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to tax credits. Including, but not limited to, research credit, foreign tax credit, investment tax credit, and other tax credits.",
        "label": "Effective Income Tax Rate Reconciliation, Tax Credit, Amount",
        "negatedTerseLabel": "Clean energy credit"
       }
      }
     },
     "localname": "IncomeTaxReconciliationTaxCredits",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesReconciliationOfIncomeTaxExpenseWithFederalIncomeTaxesAtStatutoryRateDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_IncomeTaxesPaidNet": {
     "auth_ref": [
      "r107"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes.",
        "label": "Income Taxes Paid, Net",
        "terseLabel": "Cash payments for income taxes"
       }
      }
     },
     "localname": "IncomeTaxesPaidNet",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_IncreaseDecreaseInAccountsPayableTrade": {
     "auth_ref": [
      "r101"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 11.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Change in recurring obligations of a business that arise from the acquisition of merchandise, materials, supplies and services used in the production and sale of goods and services.",
        "label": "Increase (Decrease) in Accounts Payable, Trade",
        "terseLabel": "Trade accounts payable"
       }
      }
     },
     "localname": "IncreaseDecreaseInAccountsPayableTrade",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_IncreaseDecreaseInAccountsReceivable": {
     "auth_ref": [
      "r101"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 8.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities",
       "weight": -1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The increase (decrease) during the reporting period in amount due within one year (or one business cycle) from customers for the credit sale of goods and services.",
        "label": "Increase (Decrease) in Accounts Receivable",
        "negatedLabel": "Accounts receivable"
       }
      }
     },
     "localname": "IncreaseDecreaseInAccountsReceivable",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable": {
     "auth_ref": [
      "r101"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 13.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The increase (decrease) during the period in the amount due for taxes based on the reporting entity's earnings or attributable to the entity's income earning process (business presence) within a given jurisdiction.",
        "label": "Increase (Decrease) in Income Taxes Payable",
        "terseLabel": "Income taxes \u2013 net"
       }
      }
     },
     "localname": "IncreaseDecreaseInAccruedIncomeTaxesPayable",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities": {
     "auth_ref": [
      "r101"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 14.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The increase (decrease) during the reporting period in the aggregate amount of obligations related to services received from employees, such as accrued salaries and bonuses, payroll taxes and fringe benefits.",
        "label": "Increase (Decrease) in Employee Related Liabilities",
        "terseLabel": "Other non-current liabilities"
       }
      }
     },
     "localname": "IncreaseDecreaseInEmployeeRelatedLiabilities",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_IncreaseDecreaseInInventories": {
     "auth_ref": [
      "r101"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 9.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities",
       "weight": -1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The increase (decrease) during the reporting period in the aggregate value of all inventory held by the reporting entity, associated with underlying transactions that are classified as operating activities.",
        "label": "Increase (Decrease) in Inventories",
        "negatedLabel": "Inventories"
       }
      }
     },
     "localname": "IncreaseDecreaseInInventories",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_IncreaseDecreaseInOperatingCapitalAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Increase (Decrease) in Operating Capital [Abstract]",
        "terseLabel": "Change in operating assets and liabilities"
       }
      }
     },
     "localname": "IncreaseDecreaseInOperatingCapitalAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_IncreaseDecreaseInOtherAccruedLiabilities": {
     "auth_ref": [
      "r101"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 12.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The increase (decrease) during the reporting period in other expenses incurred but not yet paid.",
        "label": "Increase (Decrease) in Other Accrued Liabilities",
        "terseLabel": "Accrued liabilities"
       }
      }
     },
     "localname": "IncreaseDecreaseInOtherAccruedLiabilities",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets": {
     "auth_ref": [
      "r101"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 10.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities",
       "weight": -1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of increase (decrease) in prepaid expenses, and assets classified as other.",
        "label": "Increase (Decrease) in Prepaid Expense and Other Assets",
        "negatedLabel": "Prepaid expenses and other assets"
       }
      }
     },
     "localname": "IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill": {
     "auth_ref": [
      "r199"
     ],
     "calculation": {
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails": {
       "order": 1.0,
       "parentTag": "us-gaap_IntangibleAssetsGrossExcludingGoodwill",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.",
        "label": "Indefinite-lived Intangible Assets (Excluding Goodwill)",
        "terseLabel": "Indefinite-lived intangible assets, carrying amount"
       }
      }
     },
     "localname": "IndefiniteLivedIntangibleAssetsExcludingGoodwill",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_IndefinitelivedIntangibleAssetsMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Assets, excluding financial assets and goodwill, that lack physical substance, having a projected indefinite period of benefit.",
        "label": "Indefinite-lived Intangible Assets [Member]",
        "terseLabel": "Non-amortized trade names and other [Member]"
       }
      }
     },
     "localname": "IndefinitelivedIntangibleAssetsMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_IntangibleAssetsGrossExcludingGoodwill": {
     "auth_ref": [],
     "calculation": {
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount before accumulated amortization of intangible assets, excluding goodwill.",
        "label": "Intangible Assets, Gross (Excluding Goodwill)",
        "totalLabel": "Total intangible assets, gross"
       }
      }
     },
     "localname": "IntangibleAssetsGrossExcludingGoodwill",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_IntangibleAssetsNetExcludingGoodwill": {
     "auth_ref": [
      "r190",
      "r194"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 5.0,
       "parentTag": "us-gaap_Assets",
       "weight": 1.0
      },
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.",
        "label": "Intangible Assets, Net (Excluding Goodwill)",
        "terseLabel": "INTANGIBLES \u2013 NET",
        "totalLabel": "Total intangible assets, net"
       }
      }
     },
     "localname": "IntangibleAssetsNetExcludingGoodwill",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets",
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_InterestCostsCapitalized": {
     "auth_ref": [
      "r399"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of interest capitalized during the period.",
        "label": "Interest Costs Capitalized",
        "terseLabel": "Capitalized interest costs"
       }
      }
     },
     "localname": "InterestCostsCapitalized",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_InterestIncomeExpenseNet": {
     "auth_ref": [
      "r440"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings": {
       "order": 2.0,
       "parentTag": "us-gaap_NonoperatingIncomeExpense",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The net amount of operating interest income (expense).",
        "label": "Interest Income (Expense), Net",
        "negatedTerseLabel": "Interest expense, net"
       }
      }
     },
     "localname": "InterestIncomeExpenseNet",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_InterestPaidNet": {
     "auth_ref": [
      "r95",
      "r99",
      "r107"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of cash paid for interest, excluding capitalized interest, classified as operating activity. Includes, but is not limited to, payment to settle zero-coupon bond for accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount.",
        "label": "Interest Paid, Excluding Capitalized Interest, Operating Activities",
        "terseLabel": "Cash payments for interest (net of amounts capitalized)"
       }
      }
     },
     "localname": "InterestPaidNet",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_InternalUseSoftwarePolicy": {
     "auth_ref": [
      "r108",
      "r201",
      "r202"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of accounting policy for costs incurred when both (1) the software is acquired, internally developed, or modified solely to meet the entity's internal needs, and (2) during the software's development or modification, no substantive plan exists or is being developed to market the software externally.",
        "label": "Internal Use Software, Policy [Policy Text Block]",
        "terseLabel": "CAPITALIZED SOFTWARE"
       }
      }
     },
     "localname": "InternalUseSoftwarePolicy",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_IntersegmentEliminationMember": {
     "auth_ref": [
      "r155"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Eliminating entries used in operating segment consolidation.",
        "label": "Intersegment Eliminations [Member]",
        "terseLabel": "Intersegment eliminations [Member]"
       }
      }
     },
     "localname": "IntersegmentEliminationMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_InventoryLIFOReserve": {
     "auth_ref": [
      "r50"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount by which inventory stated at last-in first-out (LIFO) is less than (in excess of) inventory stated at other inventory cost methods.",
        "label": "Inventory, LIFO Reserve",
        "terseLabel": "Inventory, LIFO Reserve"
       }
      }
     },
     "localname": "InventoryLIFOReserve",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_InventoryLIFOReserveEffectOnIncomeNet": {
     "auth_ref": [],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The difference between the change in the inventory reserve representing the cumulative difference in cost between the first in, first out and the last in, first out inventory valuation methods and any LIFO decrement which have been reflected in the statement of income during the period.",
        "label": "Inventory, LIFO Reserve, Effect on Income, Net",
        "terseLabel": "Inventory, LIFO Reserve, Effect on Income, Net"
       }
      }
     },
     "localname": "InventoryLIFOReserveEffectOnIncomeNet",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_InventoryNet": {
     "auth_ref": [
      "r2",
      "r48",
      "r175"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 3.0,
       "parentTag": "us-gaap_AssetsCurrent",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.",
        "label": "Inventory, Net",
        "terseLabel": "Inventories \u2013 net"
       }
      }
     },
     "localname": "InventoryNet",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_InventoryPolicyTextBlock": {
     "auth_ref": [
      "r8",
      "r49",
      "r108",
      "r132",
      "r176",
      "r177"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of inventory accounting policy for inventory classes, including, but not limited to, basis for determining inventory amounts, methods by which amounts are added and removed from inventory classes, loss recognition on impairment of inventories, and situations in which inventories are stated above cost.",
        "label": "Inventory, Policy [Policy Text Block]",
        "terseLabel": "INVENTORIES"
       }
      }
     },
     "localname": "InventoryPolicyTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_LandMember": {
     "auth_ref": [
      "r246"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Part of earth's surface not covered by water.",
        "label": "Land [Member]",
        "terseLabel": "Land [Member]"
       }
      }
     },
     "localname": "LandMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/PropertyBuildingsAndEquipmentDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_LeaseCostTableTextBlock": {
     "auth_ref": [
      "r416"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of lessee's lease cost. Includes, but is not limited to, interest expense for finance lease, amortization of right-of-use asset for finance lease, operating lease cost, short-term lease cost, variable lease cost and sublease income.",
        "label": "Lease, Cost [Table Text Block]",
        "terseLabel": "Schedule of Operating Lease Information"
       }
      }
     },
     "localname": "LeaseCostTableTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_LeasesAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Leases [Abstract]"
       }
      }
     },
     "localname": "LeasesAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "xbrltype": "stringItemType"
    },
    "us-gaap_LegalMattersAndContingenciesTextBlock": {
     "auth_ref": [
      "r224"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The entire disclosure for legal proceedings, legal contingencies, litigation, regulatory and environmental matters and other contingencies.",
        "label": "Legal Matters and Contingencies [Text Block]",
        "terseLabel": "CONTINGENCIES AND LEGAL MATTERS"
       }
      }
     },
     "localname": "LegalMattersAndContingenciesTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ContingenciesAndLegalMatters"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_LesseeLeaseDescriptionLineItems": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.",
        "label": "Lessee, Lease, Description [Line Items]",
        "terseLabel": "Lessee, Lease, Description [Line Items]"
       }
      }
     },
     "localname": "LesseeLeaseDescriptionLineItems",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesNarrativeDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_LesseeLeaseDescriptionTable": {
     "auth_ref": [
      "r410"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of information about lessee's leases.",
        "label": "Lessee, Lease, Description [Table]",
        "terseLabel": "Lessee, Lease, Description [Table]"
       }
      }
     },
     "localname": "LesseeLeaseDescriptionTable",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesNarrativeDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_LesseeLeasesPolicyTextBlock": {
     "auth_ref": [
      "r408"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of accounting policy for leasing arrangement entered into by lessee.",
        "label": "Lessee, Leases [Policy Text Block]",
        "terseLabel": "LEASES"
       }
      }
     },
     "localname": "LesseeLeasesPolicyTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock": {
     "auth_ref": [
      "r417"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of undiscounted cash flows of lessee's operating lease liability. Includes, but is not limited to, reconciliation of undiscounted cash flows to operating lease liability recognized in statement of financial position.",
        "label": "Lessee, Operating Lease, Liability, Maturity [Table Text Block]",
        "terseLabel": "Schedule of Maturities of Operating Lease Liabilities"
       }
      }
     },
     "localname": "LesseeOperatingLeaseLiabilityMaturityTableTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue": {
     "auth_ref": [
      "r417"
     ],
     "calculation": {
      "http://www.grainger.com/role/LeasesScheduleOfMaturitiesOfOperatingLeasesDetails": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      },
      "http://www.grainger.com/role/LeasesScheduleOfMaturitiesOfOperatingLeasesDetailsCalc2": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of lessee's undiscounted obligation for lease payments for operating lease.",
        "label": "Lessee, Operating Lease, Liability, Payments, Due",
        "totalLabel": "Total lease payments"
       }
      }
     },
     "localname": "LesseeOperatingLeaseLiabilityPaymentsDue",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesScheduleOfMaturitiesOfOperatingLeasesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive": {
     "auth_ref": [
      "r417"
     ],
     "calculation": {
      "http://www.grainger.com/role/LeasesScheduleOfMaturitiesOfOperatingLeasesDetails": {
       "order": 6.0,
       "parentTag": "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of lessee's undiscounted obligation for lease payments for operating lease, due after fifth fiscal year following latest fiscal year.",
        "label": "Lessee, Operating Lease, Liability, Payments, Due after Year Five",
        "terseLabel": "Thereafter"
       }
      }
     },
     "localname": "LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesScheduleOfMaturitiesOfOperatingLeasesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive": {
     "auth_ref": [
      "r417"
     ],
     "calculation": {
      "http://www.grainger.com/role/LeasesScheduleOfMaturitiesOfOperatingLeasesDetails": {
       "order": 5.0,
       "parentTag": "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of lessee's undiscounted obligation for lease payments for operating lease, due in fifth fiscal year following latest fiscal year.",
        "label": "Lessee, Operating Lease, Liability, Payments, Due Year Five",
        "terseLabel": "2024"
       }
      }
     },
     "localname": "LesseeOperatingLeaseLiabilityPaymentsDueYearFive",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesScheduleOfMaturitiesOfOperatingLeasesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour": {
     "auth_ref": [
      "r417"
     ],
     "calculation": {
      "http://www.grainger.com/role/LeasesScheduleOfMaturitiesOfOperatingLeasesDetails": {
       "order": 4.0,
       "parentTag": "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of lessee's undiscounted obligation for lease payments for operating lease, due in fourth fiscal year following latest fiscal year.",
        "label": "Lessee, Operating Lease, Liability, Payments, Due Year Four",
        "terseLabel": "2023"
       }
      }
     },
     "localname": "LesseeOperatingLeaseLiabilityPaymentsDueYearFour",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesScheduleOfMaturitiesOfOperatingLeasesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree": {
     "auth_ref": [
      "r417"
     ],
     "calculation": {
      "http://www.grainger.com/role/LeasesScheduleOfMaturitiesOfOperatingLeasesDetails": {
       "order": 3.0,
       "parentTag": "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of lessee's undiscounted obligation for lease payments for operating lease, due in third fiscal year following latest fiscal year.",
        "label": "Lessee, Operating Lease, Liability, Payments, Due Year Three",
        "terseLabel": "2022"
       }
      }
     },
     "localname": "LesseeOperatingLeaseLiabilityPaymentsDueYearThree",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesScheduleOfMaturitiesOfOperatingLeasesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo": {
     "auth_ref": [
      "r417"
     ],
     "calculation": {
      "http://www.grainger.com/role/LeasesScheduleOfMaturitiesOfOperatingLeasesDetails": {
       "order": 2.0,
       "parentTag": "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of lessee's undiscounted obligation for lease payments for operating lease, due in second fiscal year following latest fiscal year.",
        "label": "Lessee, Operating Lease, Liability, Payments, Due Year Two",
        "terseLabel": "2021"
       }
      }
     },
     "localname": "LesseeOperatingLeaseLiabilityPaymentsDueYearTwo",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesScheduleOfMaturitiesOfOperatingLeasesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear": {
     "auth_ref": [
      "r417"
     ],
     "calculation": {
      "http://www.grainger.com/role/LeasesScheduleOfMaturitiesOfOperatingLeasesDetails": {
       "order": 1.0,
       "parentTag": "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of lessee's undiscounted obligation for lease payments for operating lease having an initial or remaining lease term in excess of one year due in remainder of fiscal year following latest fiscal year.",
        "label": "Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year",
        "terseLabel": "2020"
       }
      }
     },
     "localname": "LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesScheduleOfMaturitiesOfOperatingLeasesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount": {
     "auth_ref": [
      "r417"
     ],
     "calculation": {
      "http://www.grainger.com/role/LeasesScheduleOfMaturitiesOfOperatingLeasesDetailsCalc2": {
       "order": 1.0,
       "parentTag": "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for operating lease.",
        "label": "Lessee, Operating Lease, Liability, Undiscounted Excess Amount",
        "negatedTerseLabel": "Less interest"
       }
      }
     },
     "localname": "LesseeOperatingLeaseLiabilityUndiscountedExcessAmount",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesScheduleOfMaturitiesOfOperatingLeasesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_LesseeOperatingLeaseRenewalTerm": {
     "auth_ref": [
      "r409"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.",
        "label": "Lessee, Operating Lease, Renewal Term",
        "terseLabel": "Operating lease renewal term"
       }
      }
     },
     "localname": "LesseeOperatingLeaseRenewalTerm",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "durationItemType"
    },
    "us-gaap_LesseeOperatingLeasesTextBlock": {
     "auth_ref": [
      "r419"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The entire disclosure for operating leases of lessee. Includes, but is not limited to, description of operating lease and maturity analysis of operating lease liability.",
        "label": "Lessee, Operating Leases [Text Block]",
        "terseLabel": "LEASES"
       }
      }
     },
     "localname": "LesseeOperatingLeasesTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Leases"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_LiabilitiesAndStockholdersEquity": {
     "auth_ref": [
      "r27",
      "r435",
      "r454"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of liabilities and equity items, including the portion of equity attributable to noncontrolling interests, if any.",
        "label": "Liabilities and Equity",
        "totalLabel": "TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY"
       }
      }
     },
     "localname": "LiabilitiesAndStockholdersEquity",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_LiabilitiesAndStockholdersEquityAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Liabilities and Equity [Abstract]",
        "terseLabel": "LIABILITIES AND SHAREHOLDERS' EQUITY"
       }
      }
     },
     "localname": "LiabilitiesAndStockholdersEquityAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_LiabilitiesCurrent": {
     "auth_ref": [
      "r42"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 1.0,
       "parentTag": "us-gaap_LiabilitiesAndStockholdersEquity",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Total obligations incurred as part of normal operations that are expected to be paid during the following twelve months or within one business cycle, if longer.",
        "label": "Liabilities, Current",
        "totalLabel": "Total current liabilities"
       }
      }
     },
     "localname": "LiabilitiesCurrent",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_LiabilitiesCurrentAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Liabilities, Current [Abstract]",
        "terseLabel": "CURRENT LIABILITIES"
       }
      }
     },
     "localname": "LiabilitiesCurrentAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_LineOfCredit": {
     "auth_ref": [
      "r16",
      "r433",
      "r446"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.",
        "label": "Long-term Line of Credit",
        "verboseLabel": "Line of credit, outstanding"
       }
      }
     },
     "localname": "LineOfCredit",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ShortTermDebtDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity": {
     "auth_ref": [
      "r38"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.",
        "label": "Line of Credit Facility, Maximum Borrowing Capacity",
        "terseLabel": "Maximum borrowing capacity",
        "verboseLabel": "Line of credit, maximum borrowing capacity"
       }
      }
     },
     "localname": "LineOfCreditFacilityMaximumBorrowingCapacity",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/ShortTermDebtDetails",
      "http://www.grainger.com/role/SubsequentEventDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_LineOfCreditMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "A contractual arrangement with a lender under which borrowings can be made up to a specific amount at any point in time, and under which borrowings outstanding may be either short-term or long-term, depending upon the particulars.",
        "label": "Line of Credit [Member]",
        "terseLabel": "Line of credit [Member]"
       }
      }
     },
     "localname": "LineOfCreditMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/ShortTermDebtDetails",
      "http://www.grainger.com/role/SubsequentEventDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_LinesOfCreditCurrent": {
     "auth_ref": [
      "r14",
      "r429"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The carrying value as of the balance sheet date of the current portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.",
        "label": "Line of Credit, Current",
        "terseLabel": "Lines of credit"
       }
      }
     },
     "localname": "LinesOfCreditCurrent",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ShortTermDebtDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_LondonInterbankOfferedRateLIBORMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Interest rate at which a bank borrows funds from other banks in the London interbank market.",
        "label": "London Interbank Offered Rate (LIBOR) [Member]",
        "terseLabel": "London Interbank Offered Rate (LIBOR) [Member]"
       }
      }
     },
     "localname": "LondonInterbankOfferedRateLIBORMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_LongTermDebtAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Long-term Debt, Unclassified [Abstract]"
       }
      }
     },
     "localname": "LongTermDebtAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "xbrltype": "stringItemType"
    },
    "us-gaap_LongTermDebtByMaturityAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Long-term Debt, Fiscal Year Maturity [Abstract]",
        "terseLabel": "Long-term Debt, Fiscal Year Maturity [Abstract]"
       }
      }
     },
     "localname": "LongTermDebtByMaturityAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtScheduledAggregatePrincipalPaymentsDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_LongTermDebtCurrent": {
     "auth_ref": [
      "r40"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 2.0,
       "parentTag": "us-gaap_LiabilitiesCurrent",
       "weight": 1.0
      },
      "http://www.grainger.com/role/LongTermDebtScheduledAggregatePrincipalPaymentsDetails": {
       "order": 1.0,
       "parentTag": "us-gaap_DebtInstrumentCarryingAmount",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.",
        "label": "Long-term Debt, Current Maturities",
        "negatedLabel": "Less current maturities",
        "terseLabel": "Current maturities of long-term debt",
        "verboseLabel": "2020"
       }
      }
     },
     "localname": "LongTermDebtCurrent",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets",
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails",
      "http://www.grainger.com/role/LongTermDebtScheduledAggregatePrincipalPaymentsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_LongTermDebtFairValue": {
     "auth_ref": [],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.",
        "label": "Long-term Debt, Fair Value",
        "terseLabel": "Long-term Debt, Fair Value"
       }
      }
     },
     "localname": "LongTermDebtFairValue",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive": {
     "auth_ref": [
      "r120",
      "r227"
     ],
     "calculation": {
      "http://www.grainger.com/role/LongTermDebtScheduledAggregatePrincipalPaymentsDetails": {
       "order": 6.0,
       "parentTag": "us-gaap_DebtInstrumentCarryingAmount",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.",
        "label": "Long-term Debt, Maturities, Repayments of Principal after Year Five",
        "terseLabel": "Thereafter"
       }
      }
     },
     "localname": "LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtScheduledAggregatePrincipalPaymentsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive": {
     "auth_ref": [
      "r120",
      "r227"
     ],
     "calculation": {
      "http://www.grainger.com/role/LongTermDebtScheduledAggregatePrincipalPaymentsDetails": {
       "order": 5.0,
       "parentTag": "us-gaap_DebtInstrumentCarryingAmount",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.",
        "label": "Long-term Debt, Maturities, Repayments of Principal in Year Five",
        "terseLabel": "2024"
       }
      }
     },
     "localname": "LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtScheduledAggregatePrincipalPaymentsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour": {
     "auth_ref": [
      "r120",
      "r227"
     ],
     "calculation": {
      "http://www.grainger.com/role/LongTermDebtScheduledAggregatePrincipalPaymentsDetails": {
       "order": 4.0,
       "parentTag": "us-gaap_DebtInstrumentCarryingAmount",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.",
        "label": "Long-term Debt, Maturities, Repayments of Principal in Year Four",
        "terseLabel": "2023"
       }
      }
     },
     "localname": "LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtScheduledAggregatePrincipalPaymentsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree": {
     "auth_ref": [
      "r120",
      "r227"
     ],
     "calculation": {
      "http://www.grainger.com/role/LongTermDebtScheduledAggregatePrincipalPaymentsDetails": {
       "order": 3.0,
       "parentTag": "us-gaap_DebtInstrumentCarryingAmount",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.",
        "label": "Long-term Debt, Maturities, Repayments of Principal in Year Three",
        "terseLabel": "2022"
       }
      }
     },
     "localname": "LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtScheduledAggregatePrincipalPaymentsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo": {
     "auth_ref": [
      "r120",
      "r227"
     ],
     "calculation": {
      "http://www.grainger.com/role/LongTermDebtScheduledAggregatePrincipalPaymentsDetails": {
       "order": 2.0,
       "parentTag": "us-gaap_DebtInstrumentCarryingAmount",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.",
        "label": "Long-term Debt, Maturities, Repayments of Principal in Year Two",
        "terseLabel": "2021"
       }
      }
     },
     "localname": "LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtScheduledAggregatePrincipalPaymentsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_LongTermDebtNoncurrent": {
     "auth_ref": [
      "r44"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 2.0,
       "parentTag": "us-gaap_LiabilitiesAndStockholdersEquity",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.",
        "label": "Long-term Debt, Excluding Current Maturities",
        "terseLabel": "LONG-TERM DEBT (less current maturities)",
        "verboseLabel": "Long-term debt (less current maturities and debt issuance costs and discounts)"
       }
      }
     },
     "localname": "LongTermDebtNoncurrent",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets",
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_LongTermDebtTextBlock": {
     "auth_ref": [
      "r232"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The entire disclosure for long-term debt.",
        "label": "Long-term Debt [Text Block]",
        "terseLabel": "LONG-TERM DEBT"
       }
      }
     },
     "localname": "LongTermDebtTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebt"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_LongtermDebtTypeAxis": {
     "auth_ref": [
      "r44"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by type of long-term debt.",
        "label": "Long-term Debt, Type [Axis]",
        "terseLabel": "Long-term Debt, Type [Axis]"
       }
      }
     },
     "localname": "LongtermDebtTypeAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails",
      "http://www.grainger.com/role/ShortTermDebtDetails",
      "http://www.grainger.com/role/SubsequentEventDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_LongtermDebtTypeDomain": {
     "auth_ref": [
      "r44",
      "r228"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Type of long-term debt arrangement, such as notes, line of credit, commercial paper, asset-based financing, project financing, letter of credit financing. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the company, if longer.",
        "label": "Long-term Debt, Type [Domain]",
        "terseLabel": "Long-term Debt, Type [Domain]"
       }
      }
     },
     "localname": "LongtermDebtTypeDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails",
      "http://www.grainger.com/role/ShortTermDebtDetails",
      "http://www.grainger.com/role/SubsequentEventDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_MaterialReconcilingItemsMember": {
     "auth_ref": [
      "r155",
      "r156"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Items used in reconciling reportable segments' amounts to consolidated amount. Excludes corporate-level activity.",
        "label": "Segment Reconciling Items [Member]",
        "verboseLabel": "Segment other current and noncurrent assets [Member]"
       }
      }
     },
     "localname": "MaterialReconcilingItemsMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_MinorityInterest": {
     "auth_ref": [
      "r47",
      "r434",
      "r453"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 2.0,
       "parentTag": "us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which is directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent (that is, noncontrolling interest, previously referred to as minority interest).",
        "label": "Stockholders' Equity Attributable to Noncontrolling Interest",
        "terseLabel": "Noncontrolling interest"
       }
      }
     },
     "localname": "MinorityInterest",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_NetCashProvidedByUsedInFinancingActivities": {
     "auth_ref": [
      "r98"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 3.0,
       "parentTag": "us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of cash inflow (outflow) from financing activities, including discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit.",
        "label": "Net Cash Provided by (Used in) Financing Activities",
        "totalLabel": "Net cash used in financing activities"
       }
      }
     },
     "localname": "NetCashProvidedByUsedInFinancingActivities",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Net Cash Provided by (Used in) Financing Activities [Abstract]",
        "terseLabel": "CASH FLOWS FROM FINANCING ACTIVITIES:"
       }
      }
     },
     "localname": "NetCashProvidedByUsedInFinancingActivitiesAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_NetCashProvidedByUsedInInvestingActivities": {
     "auth_ref": [
      "r98"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 2.0,
       "parentTag": "us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of cash inflow (outflow) from investing activities, including discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets.",
        "label": "Net Cash Provided by (Used in) Investing Activities",
        "totalLabel": "Net cash used in investing activities"
       }
      }
     },
     "localname": "NetCashProvidedByUsedInInvestingActivities",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Net Cash Provided by (Used in) Investing Activities [Abstract]",
        "terseLabel": "CASH FLOWS FROM INVESTING ACTIVITIES:"
       }
      }
     },
     "localname": "NetCashProvidedByUsedInInvestingActivitiesAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_NetCashProvidedByUsedInOperatingActivities": {
     "auth_ref": [
      "r98",
      "r100",
      "r103"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 1.0,
       "parentTag": "us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease",
       "weight": 1.0
      }
     },
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities.",
        "label": "Net Cash Provided by (Used in) Operating Activities",
        "totalLabel": "Net cash provided by operating activities"
       }
      }
     },
     "localname": "NetCashProvidedByUsedInOperatingActivities",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Net Cash Provided by (Used in) Operating Activities [Abstract]",
        "terseLabel": "CASH FLOWS FROM OPERATING ACTIVITIES:"
       }
      }
     },
     "localname": "NetCashProvidedByUsedInOperatingActivitiesAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_NetIncomeLoss": {
     "auth_ref": [
      "r64",
      "r67",
      "r73",
      "r103",
      "r130",
      "r438",
      "r457"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.",
        "label": "Net Income (Loss) Attributable to Parent",
        "terseLabel": "Net earnings attributable to W.W. Grainger, Inc.",
        "totalLabel": "Net earnings attributable to W.W. Grainger, Inc."
       }
      }
     },
     "localname": "NetIncomeLoss",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings",
      "http://www.grainger.com/role/SelectedQuarterlyFinancialDataUnauditedDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_NetIncomeLossAttributableToNoncontrollingInterest": {
     "auth_ref": [
      "r64",
      "r67",
      "r377",
      "r383"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings": {
       "order": 3.0,
       "parentTag": "us-gaap_ComprehensiveIncomeNetOfTax",
       "weight": -1.0
      },
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings": {
       "order": 2.0,
       "parentTag": "us-gaap_NetIncomeLoss",
       "weight": -1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of Net Income (Loss) attributable to noncontrolling interest.",
        "label": "Net Income (Loss) Attributable to Noncontrolling Interest",
        "terseLabel": "Less: Net earnings attributable to noncontrolling interest",
        "verboseLabel": "Net earnings"
       }
      }
     },
     "localname": "NetIncomeLossAttributableToNoncontrollingInterest",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings",
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of accounting policy pertaining to new accounting pronouncements that may impact the entity's financial reporting. Includes, but is not limited to, quantification of the expected or actual impact.",
        "label": "New Accounting Pronouncements, Policy [Policy Text Block]",
        "terseLabel": "NEW ACCOUNTING STANDARDS"
       }
      }
     },
     "localname": "NewAccountingPronouncementsPolicyPolicyTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance": {
     "auth_ref": [
      "r239",
      "r374",
      "r379"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of increase in noncontrolling interest from subsidiary issuance of equity interests to noncontrolling interest holders.",
        "label": "Noncontrolling Interest, Increase from Subsidiary Equity Issuance",
        "terseLabel": "Capital contribution"
       }
      }
     },
     "localname": "NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfShareholdersEquity"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_NoncontrollingInterestMember": {
     "auth_ref": [
      "r369"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "This element represents that portion of equity (net assets) in a subsidiary not attributable, directly or indirectly, to the parent. A noncontrolling interest is sometimes called a minority interest.",
        "label": "Noncontrolling Interest [Member]",
        "terseLabel": "Noncontrolling Interest [Member]"
       }
      }
     },
     "localname": "NoncontrollingInterestMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfShareholdersEquity"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_NoncurrentAssets": {
     "auth_ref": [
      "r160"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Long-lived assets other than financial instruments, long-term customer relationships of a financial institution, mortgage and other servicing rights, deferred policy acquisition costs, and deferred tax assets.",
        "label": "Long-Lived Assets",
        "terseLabel": "Long-lived assets"
       }
      }
     },
     "localname": "NoncurrentAssets",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_NonoperatingIncomeExpense": {
     "auth_ref": [
      "r79"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings": {
       "order": 2.0,
       "parentTag": "us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The aggregate amount of income or expense from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business).",
        "label": "Nonoperating Income (Expense)",
        "negatedTotalLabel": "Total other expense, net"
       }
      }
     },
     "localname": "NonoperatingIncomeExpense",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_NonoperatingIncomeExpenseAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Nonoperating Income (Expense) [Abstract]",
        "terseLabel": "Other (income) expense:"
       }
      }
     },
     "localname": "NonoperatingIncomeExpenseAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_NumberOfReportableSegments": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.",
        "label": "Number of Reportable Segments",
        "terseLabel": "Number of reportable segments"
       }
      }
     },
     "localname": "NumberOfReportableSegments",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "integerItemType"
    },
    "us-gaap_OperatingIncomeLoss": {
     "auth_ref": [],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings": {
       "order": 1.0,
       "parentTag": "us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The net result for the period of deducting operating expenses from operating revenues.",
        "label": "Operating Income (Loss)",
        "terseLabel": "Operating earnings",
        "totalLabel": "Operating earnings"
       }
      }
     },
     "localname": "OperatingIncomeLoss",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings",
      "http://www.grainger.com/role/SegmentInformationDetails",
      "http://www.grainger.com/role/SelectedQuarterlyFinancialDataUnauditedDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OperatingLeaseCost": {
     "auth_ref": [
      "r411",
      "r418"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability.",
        "label": "Operating Lease, Cost",
        "terseLabel": "Rent expense included in SG&amp;A"
       }
      }
     },
     "localname": "OperatingLeaseCost",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesScheduleOfOperatingLeaseInformationDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OperatingLeaseLiability": {
     "auth_ref": [
      "r406"
     ],
     "calculation": {
      "http://www.grainger.com/role/LeasesScheduleOfMaturitiesOfOperatingLeasesDetailsCalc2": {
       "order": 2.0,
       "parentTag": "us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue",
       "weight": 1.0
      },
      "http://www.grainger.com/role/LeasesScheduleOfOperatingLeaseInformationDetails": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Present value of lessee's discounted obligation for lease payments from operating lease.",
        "label": "Operating Lease, Liability",
        "terseLabel": "Present value of lease liabilities",
        "totalLabel": "Total operating lease liabilities"
       }
      }
     },
     "localname": "OperatingLeaseLiability",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesScheduleOfMaturitiesOfOperatingLeasesDetails",
      "http://www.grainger.com/role/LeasesScheduleOfOperatingLeaseInformationDetails",
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OperatingLeaseLiabilityCurrent": {
     "auth_ref": [
      "r406"
     ],
     "calculation": {
      "http://www.grainger.com/role/LeasesScheduleOfOperatingLeaseInformationDetails": {
       "order": 1.0,
       "parentTag": "us-gaap_OperatingLeaseLiability",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Present value of lessee's discounted obligation for lease payments from operating lease, classified as current.",
        "label": "Operating Lease, Liability, Current",
        "terseLabel": "Accrued expenses"
       }
      }
     },
     "localname": "OperatingLeaseLiabilityCurrent",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesScheduleOfOperatingLeaseInformationDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OperatingLeaseLiabilityNoncurrent": {
     "auth_ref": [
      "r406"
     ],
     "calculation": {
      "http://www.grainger.com/role/LeasesScheduleOfOperatingLeaseInformationDetails": {
       "order": 2.0,
       "parentTag": "us-gaap_OperatingLeaseLiability",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Present value of lessee's discounted obligation for lease payments from operating lease, classified as noncurrent.",
        "label": "Operating Lease, Liability, Noncurrent",
        "terseLabel": "Other non-current liabilities"
       }
      }
     },
     "localname": "OperatingLeaseLiabilityNoncurrent",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesScheduleOfOperatingLeaseInformationDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OperatingLeasePayments": {
     "auth_ref": [
      "r407",
      "r412"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of cash outflow from operating lease, excluding payments to bring another asset to condition and location necessary for its intended use.",
        "label": "Operating Lease, Payments",
        "terseLabel": "Cash paid for operating leases"
       }
      }
     },
     "localname": "OperatingLeasePayments",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesScheduleOfOperatingLeaseInformationDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OperatingLeaseRightOfUseAsset": {
     "auth_ref": [
      "r405"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of lessee's right to use underlying asset under operating lease.",
        "label": "Operating Lease, Right-of-Use Asset",
        "terseLabel": "Operating Lease, Right-of-Use Asset"
       }
      }
     },
     "localname": "OperatingLeaseRightOfUseAsset",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesScheduleOfOperatingLeaseInformationDetails",
      "http://www.grainger.com/role/SegmentInformationDetails",
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent": {
     "auth_ref": [
      "r415",
      "r418"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Weighted average discount rate for operating lease calculated at point in time.",
        "label": "Operating Lease, Weighted Average Discount Rate, Percent",
        "terseLabel": "Weighted average incremental borrowing rate"
       }
      }
     },
     "localname": "OperatingLeaseWeightedAverageDiscountRatePercent",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesScheduleOfOperatingLeaseInformationDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1": {
     "auth_ref": [
      "r414",
      "r418"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.",
        "label": "Operating Lease, Weighted Average Remaining Lease Term",
        "terseLabel": "Weighted average remaining lease term"
       }
      }
     },
     "localname": "OperatingLeaseWeightedAverageRemainingLeaseTerm1",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesScheduleOfMaturitiesOfOperatingLeasesDetails",
      "http://www.grainger.com/role/LeasesScheduleOfOperatingLeaseInformationDetails"
     ],
     "xbrltype": "durationItemType"
    },
    "us-gaap_OperatingLeasesRentExpenseSubleaseRentals1": {
     "auth_ref": [
      "r404"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The total amount of sublease rental income recognized during the period that reduces the entity's rent expense incurred under operating leases.",
        "label": "Operating Leases, Rent Expense, Sublease Rentals",
        "terseLabel": "Sublease income"
       }
      }
     },
     "localname": "OperatingLeasesRentExpenseSubleaseRentals1",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesScheduleOfOperatingLeaseInformationDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OperatingLossCarryforwards": {
     "auth_ref": [
      "r353"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.",
        "label": "Operating Loss Carryforwards",
        "terseLabel": "Operating Loss Carryforwards"
       }
      }
     },
     "localname": "OperatingLossCarryforwards",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesIncomeTaxEffectsOfTemporaryDifferencesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OperatingSegmentsMember": {
     "auth_ref": [
      "r150",
      "r157"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Identifies components of an entity that engage in business activities from which they may earn revenue and incur expenses, including transactions with other components of the same entity.",
        "label": "Operating Segments [Member]",
        "verboseLabel": "Segments"
       }
      }
     },
     "localname": "OperatingSegmentsMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_OtherAssetsNoncurrent": {
     "auth_ref": [
      "r35"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 2.0,
       "parentTag": "us-gaap_Assets",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of noncurrent assets classified as other.",
        "label": "Other Assets, Noncurrent",
        "terseLabel": "OTHER ASSETS"
       }
      }
     },
     "localname": "OtherAssetsNoncurrent",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax": {
     "auth_ref": [
      "r58"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of tax expense (benefit) for (increase) decrease in value of benefit obligation for change in actuarial assumptions and increase (decrease) in value of plan assets from experience different from that assumed of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.",
        "label": "Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax",
        "terseLabel": "Postretirement benefit plan re-measurement, net of tax"
       }
      }
     },
     "localname": "OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest": {
     "auth_ref": [
      "r371",
      "r372",
      "r380"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings": {
       "order": 2.0,
       "parentTag": "us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature, attributable to noncontrolling interests.",
        "label": "Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Noncontrolling Interest",
        "terseLabel": "Foreign currency translation adjustments"
       }
      }
     },
     "localname": "OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax": {
     "auth_ref": [
      "r53",
      "r57",
      "r395",
      "r396",
      "r397",
      "r398"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings": {
       "order": 2.0,
       "parentTag": "us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount after tax, before reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.",
        "label": "Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax",
        "terseLabel": "Foreign currency translation adjustments, net of reclassification (see Note 5 and Note 12)"
       }
      }
     },
     "localname": "OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OtherComprehensiveIncomeLocationAxis": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by location in other comprehensive income.",
        "label": "Other Comprehensive Income Location [Axis]",
        "terseLabel": "Other Comprehensive Income Location [Axis]"
       }
      }
     },
     "localname": "OtherComprehensiveIncomeLocationAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails",
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_OtherComprehensiveIncomeLocationDomain": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Location in other comprehensive income.",
        "label": "Other Comprehensive Income Location [Domain]",
        "terseLabel": "Other Comprehensive Income Location [Domain]"
       }
      }
     },
     "localname": "OtherComprehensiveIncomeLocationDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails",
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax": {
     "auth_ref": [
      "r60",
      "r71"
     ],
     "calculation": {
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails": {
       "order": 1.0,
       "parentTag": "us-gaap_OtherComprehensiveIncomeLossNetOfTax",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount after tax, before reclassification adjustments of other comprehensive income (loss).",
        "label": "Other Comprehensive Income (Loss), before Reclassifications, Net of Tax",
        "terseLabel": "Other comprehensive earnings (loss) before reclassifications, net of tax"
       }
      }
     },
     "localname": "OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OtherComprehensiveIncomeLossNetOfTax": {
     "auth_ref": [
      "r65",
      "r68",
      "r71",
      "r233"
     ],
     "calculation": {
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount after tax and reclassification adjustments of other comprehensive income (loss).",
        "label": "Other Comprehensive Income (Loss), Net of Tax",
        "terseLabel": "Total other comprehensive (losses) earnings",
        "totalLabel": "Net current period activity",
        "verboseLabel": "Other comprehensive earnings (losses)"
       }
      }
     },
     "localname": "OtherComprehensiveIncomeLossNetOfTax",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails",
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings",
      "http://www.grainger.com/role/ConsolidatedStatementsOfShareholdersEquity"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Other Comprehensive Income (Loss), Net of Tax [Abstract]",
        "terseLabel": "Other comprehensive earnings (losses):"
       }
      }
     },
     "localname": "OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeReclassificationAdjustmentsNetOfTax": {
     "auth_ref": [
      "r55",
      "r57"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings": {
       "order": 3.0,
       "parentTag": "us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest",
       "weight": -1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount, after tax, before reclassification adjustment, of (increase) decrease in accumulated other comprehensive income of defined benefit plan, that has not been recognized in net periodic benefit cost (credit).",
        "label": "Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, after Tax",
        "negatedTerseLabel": "Postretirement benefit plan re-measurement, net of tax expense $29 million (see Note 8 and Note 12)"
       }
      }
     },
     "localname": "OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeReclassificationAdjustmentsNetOfTax",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossTax": {
     "auth_ref": [
      "r58"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan.",
        "label": "Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, Tax",
        "terseLabel": "Postretirement benefit plan remeasurement, net of tax expense"
       }
      }
     },
     "localname": "OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossTax",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarningsParentheticals"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax": {
     "auth_ref": [
      "r57",
      "r61",
      "r62",
      "r281"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings": {
       "order": 4.0,
       "parentTag": "us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount, after tax, of reclassification adjustment from accumulated other comprehensive (income) loss for net periodic benefit cost (credit) of defined benefit plan.",
        "label": "Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax",
        "terseLabel": "Postretirement benefit plan reclassification, net of tax benefit of $2 million, $3 million and $1 million, respectively"
       }
      }
     },
     "localname": "OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax": {
     "auth_ref": [
      "r58",
      "r371"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of tax (expense) benefit for reclassification adjustment from accumulated other comprehensive (income) loss of defined benefit plan.",
        "label": "Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax",
        "terseLabel": "Postretirement benefit plan reclassification, net of tax benefit"
       }
      }
     },
     "localname": "OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarningsParentheticals"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OtherIncomeTaxExpenseBenefitContinuingOperations": {
     "auth_ref": [
      "r335",
      "r357"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 3.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of other current and other deferred income tax expense (benefit) attributable to continuing operations.",
        "label": "Other Income Tax Expense (Benefit), Continuing Operations",
        "verboseLabel": "Deferred income taxes and tax uncertainties"
       }
      }
     },
     "localname": "OtherIncomeTaxExpenseBenefitContinuingOperations",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OtherLongTermDebt": {
     "auth_ref": [
      "r16",
      "r433",
      "r451"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of long-term debt classified as other.",
        "label": "Other Long-term Debt",
        "terseLabel": "Other"
       }
      }
     },
     "localname": "OtherLongTermDebt",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OtherNonoperatingIncomeExpense": {
     "auth_ref": [
      "r80"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings": {
       "order": 1.0,
       "parentTag": "us-gaap_NonoperatingIncomeExpense",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of income (expense) related to nonoperating activities, classified as other.",
        "label": "Other Nonoperating Income (Expense)",
        "negatedTerseLabel": "Other, net"
       }
      }
     },
     "localname": "OtherNonoperatingIncomeExpense",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OtherPensionPlansPostretirementOrSupplementalPlansDefinedBenefitMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Pension plan, other postretirement plan, and supplemental retirement plan, classified as other. Includes, but is not limited to, defined benefit and defined contribution plans.",
        "label": "Other Pension, Postretirement and Supplemental Plans [Member]",
        "terseLabel": "Other Employment-related Benefit Plans"
       }
      }
     },
     "localname": "OtherPensionPlansPostretirementOrSupplementalPlansDefinedBenefitMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember": {
     "auth_ref": [
      "r256",
      "r288",
      "r289",
      "r300"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Plan designed to provide other postretirement benefits. Includes, but is not limited to, defined benefit and defined contribution plans. Excludes pension benefits.",
        "label": "Other Postretirement Benefits Plan [Member]",
        "terseLabel": "Postretirement Benefits [Member]"
       }
      }
     },
     "localname": "OtherPostretirementBenefitPlansDefinedBenefitMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_OtherPostretirementDefinedBenefitPlanLiabilitiesCurrentAndNoncurrent": {
     "auth_ref": [
      "r257",
      "r270",
      "r432",
      "r449"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 5.0,
       "parentTag": "us-gaap_LiabilitiesCurrent",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of liability, recognized in statement of financial position, for defined benefit other postretirement plan. Excludes pension plan.",
        "label": "Liability, Other Postretirement Defined Benefit Plan",
        "terseLabel": "Accrued contributions to employees\u2019 profit-sharing plans"
       }
      }
     },
     "localname": "OtherPostretirementDefinedBenefitPlanLiabilitiesCurrentAndNoncurrent",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_OtherPostretirementDefinedBenefitPlanLiabilitiesNoncurrent": {
     "auth_ref": [
      "r17",
      "r257",
      "r258",
      "r270"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 4.0,
       "parentTag": "us-gaap_LiabilitiesAndStockholdersEquity",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of liability, recognized in statement of financial position, for defined benefit other postretirement plan, classified as noncurrent. Excludes pension plan.",
        "label": "Liability, Other Postretirement Defined Benefit Plan, Noncurrent",
        "terseLabel": "OTHER NON-CURRENT LIABILITIES"
       }
      }
     },
     "localname": "OtherPostretirementDefinedBenefitPlanLiabilitiesNoncurrent",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_PaymentsForProceedsFromOtherInvestingActivities": {
     "auth_ref": [
      "r85",
      "r88",
      "r119"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 3.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInInvestingActivities",
       "weight": -1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of cash (inflow) outflow from investing activities classified as other.",
        "label": "Payments for (Proceeds from) Other Investing Activities",
        "negatedLabel": "Other \u2013 net"
       }
      }
     },
     "localname": "PaymentsForProceedsFromOtherInvestingActivities",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_PaymentsForRepurchaseOfCommonStock": {
     "auth_ref": [
      "r92"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 7.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities",
       "weight": -1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The cash outflow to reacquire common stock during the period.",
        "label": "Payments for Repurchase of Common Stock",
        "negatedLabel": "Purchases of treasury stock"
       }
      }
     },
     "localname": "PaymentsForRepurchaseOfCommonStock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_PaymentsOfDividendsCommonStock": {
     "auth_ref": [
      "r92"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 8.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities",
       "weight": -1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity.",
        "label": "Payments of Ordinary Dividends, Common Stock",
        "negatedLabel": "Cash dividends paid"
       }
      }
     },
     "localname": "PaymentsOfDividendsCommonStock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_PaymentsToAcquireEquityMethodInvestments": {
     "auth_ref": [
      "r86"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 5.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInInvestingActivities",
       "weight": -1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.",
        "label": "Payments to Acquire Equity Method Investments",
        "negatedTerseLabel": "Equity method proceeds (investment)"
       }
      }
     },
     "localname": "PaymentsToAcquireEquityMethodInvestments",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_PaymentsToAcquirePropertyPlantAndEquipment": {
     "auth_ref": [
      "r87"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 1.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInInvestingActivities",
       "weight": -1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets.",
        "label": "Payments to Acquire Property, Plant, and Equipment",
        "negatedLabel": "Additions to property, buildings, equipment and intangibles"
       }
      }
     },
     "localname": "PaymentsToAcquirePropertyPlantAndEquipment",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_PensionAndOtherPostretirementBenefitExpense": {
     "auth_ref": [],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of cost (reversal of cost) for pension and other postretirement benefits.",
        "label": "Pension and Other Postretirement Benefits Cost (Reversal of Cost)",
        "terseLabel": "Pension and Other Postretirement Benefits Cost (Reversal of Cost)",
        "verboseLabel": "Profit sharing plan expense"
       }
      }
     },
     "localname": "PensionAndOtherPostretirementBenefitExpense",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsDefinedContributionPlansDetails",
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_PensionAndOtherPostretirementBenefitExpenseAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]",
        "terseLabel": "Postretirement Benefits"
       }
      }
     },
     "localname": "PensionAndOtherPostretirementBenefitExpenseAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock": {
     "auth_ref": [
      "r301"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The entire disclosure for pension and other postretirement benefits.",
        "label": "Pension and Other Postretirement Benefits Disclosure [Text Block]",
        "terseLabel": "EMPLOYEE BENEFITS"
       }
      }
     },
     "localname": "PensionAndOtherPostretirementBenefitsDisclosureTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefits"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent": {
     "auth_ref": [
      "r17",
      "r257",
      "r258",
      "r270"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of liability, recognized in statement of financial position, for defined benefit pension and other postretirement plans, classified as noncurrent.",
        "label": "Liability, Defined Benefit Plan, Noncurrent",
        "terseLabel": "Noncurrent postretirement benefit obligation"
       }
      }
     },
     "localname": "PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_PensionPlansDefinedBenefitMember": {
     "auth_ref": [
      "r255",
      "r288",
      "r289",
      "r300"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Plan designed to provide participant with pension benefits. Includes, but is not limited to, defined benefit and defined contribution plans. Excludes other postretirement benefits.",
        "label": "Pension Plan [Member]",
        "terseLabel": "Defined Postretirement Benefit Plan"
       }
      }
     },
     "localname": "PensionPlansDefinedBenefitMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_PercentageOfLIFOInventory": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The percentage of LIFO (last in first out) inventory to total inventory as of the balance sheet date if other than 100 percent.",
        "label": "Percentage of LIFO Inventory",
        "terseLabel": "Percentage of LIFO Inventory"
       }
      }
     },
     "localname": "PercentageOfLIFOInventory",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "us-gaap_PlanAssetCategoriesDomain": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Defined benefit plan asset investment.",
        "label": "Defined Benefit Plan, Plan Assets, Category [Domain]",
        "terseLabel": "Defined Benefit Plan, Plan Assets, Category [Domain]"
       }
      }
     },
     "localname": "PlanAssetCategoriesDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_PreferredStockParOrStatedValuePerShare": {
     "auth_ref": [
      "r20"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.",
        "label": "Preferred Stock, Par or Stated Value Per Share",
        "terseLabel": "Cumulative preferred stock, par value (in dollars per share)"
       }
      }
     },
     "localname": "PreferredStockParOrStatedValuePerShare",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheetsParentheticals"
     ],
     "xbrltype": "perShareItemType"
    },
    "us-gaap_PreferredStockSharesAuthorized": {
     "auth_ref": [
      "r20"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws.",
        "label": "Preferred Stock, Shares Authorized",
        "terseLabel": "Cumulative preferred stock, shares authorized (in shares)"
       }
      }
     },
     "localname": "PreferredStockSharesAuthorized",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheetsParentheticals"
     ],
     "xbrltype": "sharesItemType"
    },
    "us-gaap_PreferredStockSharesIssued": {
     "auth_ref": [
      "r20"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt.",
        "label": "Preferred Stock, Shares Issued",
        "terseLabel": "Cumulative preferred stock, shares issued (in shares)"
       }
      }
     },
     "localname": "PreferredStockSharesIssued",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheetsParentheticals"
     ],
     "xbrltype": "sharesItemType"
    },
    "us-gaap_PreferredStockSharesOutstanding": {
     "auth_ref": [
      "r20"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased.",
        "label": "Preferred Stock, Shares Outstanding",
        "terseLabel": "Cumulative preferred stock, shares outstanding (in shares)"
       }
      }
     },
     "localname": "PreferredStockSharesOutstanding",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/CapitalStockDetails",
      "http://www.grainger.com/role/ConsolidatedBalanceSheetsParentheticals"
     ],
     "xbrltype": "sharesItemType"
    },
    "us-gaap_PreferredStockValue": {
     "auth_ref": [
      "r20"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 1.0,
       "parentTag": "us-gaap_StockholdersEquity",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Aggregate par or stated value of issued nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable preferred shares, par value and other disclosure concepts are in another section within stockholders' equity.",
        "label": "Preferred Stock, Value, Issued",
        "terseLabel": "Cumulative Preferred Stock \u2013 $5 par value \u2013 12,000,000 shares authorized; none issued or outstanding"
       }
      }
     },
     "localname": "PreferredStockValue",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_PrepaidExpenseAndOtherAssetsCurrent": {
     "auth_ref": [
      "r5",
      "r29",
      "r30"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 4.0,
       "parentTag": "us-gaap_AssetsCurrent",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of asset related to consideration paid in advance for costs that provide economic benefits in future periods, and amount of other assets that are expected to be realized or consumed within one year or the normal operating cycle, if longer.",
        "label": "Prepaid Expense and Other Assets, Current",
        "terseLabel": "Prepaid expenses and other assets"
       }
      }
     },
     "localname": "PrepaidExpenseAndOtherAssetsCurrent",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_PrepaidTaxes": {
     "auth_ref": [
      "r4",
      "r6",
      "r178",
      "r179"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 2.0,
       "parentTag": "us-gaap_AssetsCurrent",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of asset related to consideration paid in advance for income and other taxes that provide economic benefits within a future period of one year or the normal operating cycle, if longer.",
        "label": "Prepaid Taxes",
        "terseLabel": "Prepaid income taxes"
       }
      }
     },
     "localname": "PrepaidTaxes",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_PriorPeriodReclassificationAdjustment": {
     "auth_ref": [],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The amount of a reclassification adjustment made to prior period financial statement amounts.",
        "label": "Prior Period Reclassification Adjustment",
        "terseLabel": "Reclassification due to the adoption of ASU 2018-02"
       }
      }
     },
     "localname": "PriorPeriodReclassificationAdjustment",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfShareholdersEquity"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital": {
     "auth_ref": [
      "r83",
      "r97"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 4.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInInvestingActivities",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of distribution received from equity method investee for return of investment, classified as investing activities. Excludes distribution for return on investment, classified as operating activities.",
        "label": "Proceeds from Equity Method Investment, Distribution, Return of Capital",
        "terseLabel": "Equity method proceeds (investment)"
       }
      }
     },
     "localname": "ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_ProceedsFromIssuanceOfLongTermDebt": {
     "auth_ref": [
      "r90"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 3.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.",
        "label": "Proceeds from Issuance of Long-term Debt",
        "terseLabel": "Proceeds from issuance of long-term debt"
       }
      }
     },
     "localname": "ProceedsFromIssuanceOfLongTermDebt",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_ProceedsFromLinesOfCredit": {
     "auth_ref": [
      "r90",
      "r115"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 1.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.",
        "label": "Proceeds from Lines of Credit",
        "terseLabel": "Borrowings under lines of credit"
       }
      }
     },
     "localname": "ProceedsFromLinesOfCredit",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_ProceedsFromPaymentsForOtherFinancingActivities": {
     "auth_ref": [
      "r91",
      "r94",
      "r119"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 10.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of cash inflow (outflow) from financing activities classified as other.",
        "label": "Proceeds from (Payments for) Other Financing Activities",
        "terseLabel": "Other \u2013 net"
       }
      }
     },
     "localname": "ProceedsFromPaymentsForOtherFinancingActivities",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_ProceedsFromRepaymentsOfCommercialPaper": {
     "auth_ref": [
      "r90",
      "r93",
      "r105"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 9.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The net cash inflow or cash outflow from issuing (borrowing) and repaying commercial paper.",
        "label": "Proceeds from (Repayments of) Commercial Paper",
        "terseLabel": "Net decrease in commercial paper"
       }
      }
     },
     "localname": "ProceedsFromRepaymentsOfCommercialPaper",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment": {
     "auth_ref": [
      "r84"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 2.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInInvestingActivities",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The cash inflow from the sale of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale.",
        "label": "Proceeds from Sale of Property, Plant, and Equipment",
        "terseLabel": "Proceeds from sales of assets"
       }
      }
     },
     "localname": "ProceedsFromSaleOfPropertyPlantAndEquipment",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_ProceedsFromStockOptionsExercised": {
     "auth_ref": [
      "r89",
      "r320"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 5.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of cash inflow from exercise of option under share-based payment arrangement.",
        "label": "Proceeds from Stock Options Exercised",
        "terseLabel": "Proceeds from stock options exercised"
       }
      }
     },
     "localname": "ProceedsFromStockOptionsExercised",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_ProfitLoss": {
     "auth_ref": [
      "r64",
      "r67",
      "r96",
      "r153",
      "r158",
      "r371",
      "r376",
      "r378",
      "r383",
      "r384"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 1.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities",
       "weight": 1.0
      },
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings": {
       "order": 1.0,
       "parentTag": "us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest",
       "weight": 1.0
      },
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings": {
       "order": 1.0,
       "parentTag": "us-gaap_NetIncomeLoss",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.",
        "label": "Net Income (Loss), Including Portion Attributable to Noncontrolling Interest",
        "terseLabel": "Net earnings",
        "totalLabel": "Net earnings"
       }
      }
     },
     "localname": "ProfitLoss",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows",
      "http://www.grainger.com/role/ConsolidatedStatementsOfComprehensiveEarnings",
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings",
      "http://www.grainger.com/role/ConsolidatedStatementsOfShareholdersEquity"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_PropertyPlantAndEquipmentAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Property, Plant and Equipment [Abstract]"
       }
      }
     },
     "localname": "PropertyPlantAndEquipmentAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "xbrltype": "stringItemType"
    },
    "us-gaap_PropertyPlantAndEquipmentAdditions": {
     "auth_ref": [],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of acquisition of long-lived, physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.",
        "label": "Property, Plant and Equipment, Additions",
        "terseLabel": "Additions to long-lived assets"
       }
      }
     },
     "localname": "PropertyPlantAndEquipmentAdditions",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_PropertyPlantAndEquipmentByTypeAxis": {
     "auth_ref": [
      "r34",
      "r209"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by type of long-lived, physical assets used to produce goods and services and not intended for resale.",
        "label": "Property, Plant and Equipment, Type [Axis]",
        "terseLabel": "Property, Plant and Equipment, Type [Axis]"
       }
      }
     },
     "localname": "PropertyPlantAndEquipmentByTypeAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/PropertyBuildingsAndEquipmentDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock": {
     "auth_ref": [
      "r214"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The entire disclosure for long-lived, physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, accounting policies and methodology, roll forwards, depreciation, depletion and amortization expense, including composite depreciation, accumulated depreciation, depletion and amortization expense, useful lives and method used, income statement disclosures, assets held for sale and public utility disclosures.",
        "label": "Property, Plant and Equipment Disclosure [Text Block]",
        "terseLabel": "PROPERTY, BUILDINGS AND EQUIPMENT"
       }
      }
     },
     "localname": "PropertyPlantAndEquipmentDisclosureTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/PropertyBuildingsAndEquipment"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_PropertyPlantAndEquipmentGross": {
     "auth_ref": [
      "r33",
      "r207"
     ],
     "calculation": {
      "http://www.grainger.com/role/PropertyBuildingsAndEquipmentDetails": {
       "order": 1.0,
       "parentTag": "us-gaap_PropertyPlantAndEquipmentNet",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.",
        "label": "Property, Plant and Equipment, Gross",
        "terseLabel": "PROPERTY, BUILDINGS AND EQUIPMENT"
       }
      }
     },
     "localname": "PropertyPlantAndEquipmentGross",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/PropertyBuildingsAndEquipmentDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_PropertyPlantAndEquipmentLineItems": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.",
        "label": "Property, Plant and Equipment [Line Items]",
        "terseLabel": "Property, Plant and Equipment [Line Items]"
       }
      }
     },
     "localname": "PropertyPlantAndEquipmentLineItems",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/PropertyBuildingsAndEquipmentDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_PropertyPlantAndEquipmentNet": {
     "auth_ref": [
      "r10",
      "r11",
      "r209",
      "r455"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 4.0,
       "parentTag": "us-gaap_Assets",
       "weight": 1.0
      },
      "http://www.grainger.com/role/PropertyBuildingsAndEquipmentDetails": {
       "order": null,
       "parentTag": null,
       "root": true,
       "weight": null
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.",
        "label": "Property, Plant and Equipment, Net",
        "terseLabel": "PROPERTY, BUILDINGS AND EQUIPMENT \u2013 NET",
        "totalLabel": "PROPERTY, BUILDINGS AND EQUIPMENT \u2013 NET"
       }
      }
     },
     "localname": "PropertyPlantAndEquipmentNet",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets",
      "http://www.grainger.com/role/PropertyBuildingsAndEquipmentDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_PropertyPlantAndEquipmentPolicyTextBlock": {
     "auth_ref": [
      "r32",
      "r108",
      "r209"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of accounting policy for long-lived, physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, basis of assets, depreciation and depletion methods used, including composite deprecation, estimated useful lives, capitalization policy, accounting treatment for costs incurred for repairs and maintenance, capitalized interest and the method it is calculated, disposals and impairments.",
        "label": "Property, Plant and Equipment, Policy [Policy Text Block]",
        "terseLabel": "PROPERTY, BUILDINGS AND EQUIPMENT"
       }
      }
     },
     "localname": "PropertyPlantAndEquipmentPolicyTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_PropertyPlantAndEquipmentTextBlock": {
     "auth_ref": [
      "r10",
      "r209"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, balances by class of assets, depreciation and depletion expense and method used, including composite depreciation, and accumulated deprecation.",
        "label": "Property, Plant and Equipment [Table Text Block]",
        "terseLabel": "Property, Buildings and Equipment"
       }
      }
     },
     "localname": "PropertyPlantAndEquipmentTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/PropertyBuildingsAndEquipmentTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_PropertyPlantAndEquipmentTypeDomain": {
     "auth_ref": [
      "r10",
      "r207"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Listing of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software.",
        "label": "Property, Plant and Equipment, Type [Domain]",
        "terseLabel": "Property, Plant and Equipment, Type [Domain]"
       }
      }
     },
     "localname": "PropertyPlantAndEquipmentTypeDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/PropertyBuildingsAndEquipmentDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_ProvisionForDoubtfulAccounts": {
     "auth_ref": [
      "r75",
      "r173"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 2.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of expense (reversal of expense) for expected credit loss on accounts receivable.",
        "label": "Accounts Receivable, Credit Loss Expense (Reversal)",
        "verboseLabel": "Provision for losses on accounts receivable"
       }
      }
     },
     "localname": "ProvisionForDoubtfulAccounts",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_QuarterlyFinancialInformationTextBlock": {
     "auth_ref": [
      "r134"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The entire disclosure for quarterly financial data. Includes, but is not limited to, tabular presentation of financial information for fiscal quarters, effect of year-end adjustments, and an explanation of matters or transactions that affect comparability of the information.",
        "label": "Quarterly Financial Information [Text Block]",
        "terseLabel": "SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED)"
       }
      }
     },
     "localname": "QuarterlyFinancialInformationTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SelectedQuarterlyFinancialDataUnaudited"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ReceivablesPolicyTextBlock": {
     "auth_ref": [
      "r108",
      "r166",
      "r169",
      "r170",
      "r171"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of accounting policy for receivable. Includes, but is not limited to, accounts receivable and financing receivable.",
        "label": "Receivable [Policy Text Block]",
        "terseLabel": "ACCOUNTS RECEIVABLE AND ALLOWANCE FOR DOUBTFUL ACCOUNTS"
       }
      }
     },
     "localname": "ReceivablesPolicyTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax": {
     "auth_ref": [
      "r60",
      "r63",
      "r71"
     ],
     "calculation": {
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails": {
       "order": 2.0,
       "parentTag": "us-gaap_OtherComprehensiveIncomeLossNetOfTax",
       "weight": -1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount after tax of reclassification adjustments of other comprehensive income (loss).",
        "label": "Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax",
        "negatedTerseLabel": "Amounts reclassified to Net earnings"
       }
      }
     },
     "localname": "ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.",
        "label": "AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]",
        "terseLabel": "AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]"
       }
      }
     },
     "localname": "ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.",
        "label": "Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]",
        "terseLabel": "Changes in liability for tax uncertainties, excluding interest"
       }
      }
     },
     "localname": "ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesChangesInLiabilityForTaxUncertaintiesExcludingInterestDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_RepaymentsOfLinesOfCredit": {
     "auth_ref": [
      "r93",
      "r115"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 2.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities",
       "weight": -1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.",
        "label": "Repayments of Lines of Credit",
        "negatedLabel": "Payments against lines of credit"
       }
      }
     },
     "localname": "RepaymentsOfLinesOfCredit",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_RepaymentsOfLongTermDebt": {
     "auth_ref": [
      "r93"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 4.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInFinancingActivities",
       "weight": -1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.",
        "label": "Repayments of Long-term Debt",
        "negatedLabel": "Payments of long-term debt",
        "terseLabel": "Repayments debt"
       }
      }
     },
     "localname": "RepaymentsOfLongTermDebt",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows",
      "http://www.grainger.com/role/LongTermDebtDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_RestrictedStockExpense": {
     "auth_ref": [
      "r102"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of noncash expense for award of restricted stock or unit under share-based payment arrangement.",
        "label": "Restricted Stock or Unit Expense",
        "terseLabel": "Restricted Stock or Unit Expense"
       }
      }
     },
     "localname": "RestrictedStockExpense",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_RestrictedStockUnitsRSUMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Share instrument which is convertible to stock or an equivalent amount of cash, after a specified period of time or when specified performance conditions are met.",
        "label": "Restricted Stock Units (RSUs) [Member]",
        "terseLabel": "Restricted Stock Units [Member]"
       }
      }
     },
     "localname": "RestrictedStockUnitsRSUMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansDetails",
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_RestructuringAndRelatedActivitiesAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Restructuring and Related Activities [Abstract]"
       }
      }
     },
     "localname": "RestructuringAndRelatedActivitiesAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "xbrltype": "stringItemType"
    },
    "us-gaap_RestructuringAndRelatedActivitiesDisclosureTextBlock": {
     "auth_ref": [
      "r222"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The entire disclosure for restructuring and related activities. Description of restructuring activities such as exit and disposal activities, include facts and circumstances leading to the plan, the expected plan completion date, the major types of costs associated with the plan activities, total expected costs, the accrual balance at the end of the period, and the periods over which the remaining accrual will be settled.",
        "label": "Restructuring and Related Activities Disclosure [Text Block]",
        "terseLabel": "RESTRUCTURING RESERVES"
       }
      }
     },
     "localname": "RestructuringAndRelatedActivitiesDisclosureTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RestructuringReserves"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_RestructuringCostAndReserveAxis": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by type of restructuring cost.",
        "label": "Restructuring Type [Axis]",
        "terseLabel": "Restructuring Type [Axis]"
       }
      }
     },
     "localname": "RestructuringCostAndReserveAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_RestructuringCostAndReserveLineItems": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.",
        "label": "Restructuring Cost and Reserve [Line Items]",
        "terseLabel": "Restructuring Cost and Reserve [Line Items]"
       }
      }
     },
     "localname": "RestructuringCostAndReserveLineItems",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_RestructuringCosts": {
     "auth_ref": [
      "r102"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount, after cash payment, of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.",
        "label": "Restructuring Costs",
        "terseLabel": "Restructuring Costs"
       }
      }
     },
     "localname": "RestructuringCosts",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_RestructuringPlanAxis": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by individual restructuring plan.",
        "label": "Restructuring Plan [Axis]",
        "terseLabel": "Restructuring Plan [Axis]"
       }
      }
     },
     "localname": "RestructuringPlanAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_RestructuringPlanDomain": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Identification of the individual restructuring plans.",
        "label": "Restructuring Plan [Domain]",
        "terseLabel": "Restructuring Plan [Domain]"
       }
      }
     },
     "localname": "RestructuringPlanDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_RestructuringReserve": {
     "auth_ref": [
      "r215",
      "r219"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.",
        "label": "Restructuring Reserve",
        "terseLabel": "Restructuring Reserve"
       }
      }
     },
     "localname": "RestructuringReserve",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_RetainedEarningsAccumulatedDeficit": {
     "auth_ref": [
      "r24",
      "r238",
      "r452"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 4.0,
       "parentTag": "us-gaap_StockholdersEquity",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The cumulative amount of the reporting entity's undistributed earnings or deficit.",
        "label": "Retained Earnings (Accumulated Deficit)",
        "terseLabel": "Retained earnings"
       }
      }
     },
     "localname": "RetainedEarningsAccumulatedDeficit",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_RetainedEarningsMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The cumulative amount of the reporting entity's undistributed earnings or deficit.",
        "label": "Retained Earnings [Member]",
        "terseLabel": "Retained Earnings [Member]"
       }
      }
     },
     "localname": "RetainedEarningsMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfShareholdersEquity",
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_RetirementPlanTypeAxis": {
     "auth_ref": [
      "r255",
      "r256",
      "r288",
      "r289",
      "r300"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by type of retirement benefit plan. Includes, but is not limited to, retirement benefit arrangement for defined benefit pension and other postretirement plans, retirement benefit arrangement for defined contribution pension and other postretirement plans, and special and contractual termination benefits payable upon retirement.",
        "label": "Retirement Plan Type [Axis]",
        "terseLabel": "Retirement Plan Type [Axis]"
       }
      }
     },
     "localname": "RetirementPlanTypeAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails",
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_RetirementPlanTypeDomain": {
     "auth_ref": [
      "r255",
      "r256",
      "r288",
      "r289",
      "r300"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Type of plan designed to provide participants with retirement benefits. Includes, but is not limited to, retirement benefit arrangement for defined benefit pension and other postretirement plans, retirement benefit arrangement for defined contribution pension and other postretirement plans, and special and contractual termination benefits payable upon retirement.",
        "label": "Retirement Plan Type [Domain]",
        "terseLabel": "Retirement Plan Type [Domain]"
       }
      }
     },
     "localname": "RetirementPlanTypeDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails",
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax": {
     "auth_ref": [
      "r242",
      "r243"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings": {
       "order": 1.0,
       "parentTag": "us-gaap_GrossProfit",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.",
        "label": "Revenue from Contract with Customer, Excluding Assessed Tax",
        "terseLabel": "Net sales"
       }
      }
     },
     "localname": "RevenueFromContractWithCustomerExcludingAssessedTax",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings",
      "http://www.grainger.com/role/SegmentInformationDetails",
      "http://www.grainger.com/role/SelectedQuarterlyFinancialDataUnauditedDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_RevenueFromContractWithCustomerTextBlock": {
     "auth_ref": [
      "r253"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.",
        "label": "Revenue from Contract with Customer [Text Block]",
        "terseLabel": "REVENUE"
       }
      }
     },
     "localname": "RevenueFromContractWithCustomerTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/Revenue"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_RevenueRecognitionPolicyTextBlock": {
     "auth_ref": [
      "r109",
      "r110"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of accounting policy for revenue. Includes revenue from contract with customer and from other sources.",
        "label": "Revenue [Policy Text Block]",
        "terseLabel": "REVENUE RECOGNITION"
       }
      }
     },
     "localname": "RevenueRecognitionPolicyTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_RevolvingCreditFacilityMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Arrangement in which loan proceeds can continuously be obtained following repayments, but the total amount borrowed cannot exceed a specified maximum amount.",
        "label": "Revolving Credit Facility [Member]",
        "terseLabel": "Revolving credit facility [Member]"
       }
      }
     },
     "localname": "RevolvingCreditFacilityMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/SubsequentEventDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability": {
     "auth_ref": [
      "r413",
      "r418"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of increase in right-of-use asset obtained in exchange for operating lease liability.",
        "label": "Right-of-Use Asset Obtained in Exchange for Operating Lease Liability",
        "terseLabel": "ROU assets obtained in exchange for operating lease obligations"
       }
      }
     },
     "localname": "RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LeasesScheduleOfOperatingLeaseInformationDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock": {
     "auth_ref": [
      "r60"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of the components of accumulated other comprehensive income (loss).",
        "label": "Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]",
        "terseLabel": "Schedule of AOCE"
       }
      }
     },
     "localname": "ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock": {
     "auth_ref": [
      "r271"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of the major categories of plan assets of pension plans and/or other employee benefit plans.  This information may include, but is not limited to, the target allocation of plan assets, the fair value of each major category of plan assets, and the level within the fair value hierarchy in which the fair value measurements fall.",
        "label": "Schedule of Allocation of Plan Assets [Table Text Block]",
        "terseLabel": "Schedule of Allocation of Plan Assets"
       }
      }
     },
     "localname": "ScheduleOfAllocationOfPlanAssetsTableTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ScheduleOfAmountsRecognizedInOtherComprehensiveIncomeLossTableTextBlock": {
     "auth_ref": [
      "r281"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of the net gain (loss) and net prior service cost or credit recognized in other comprehensive income (loss) for the period for pension plans and/or other employee benefit plans, and reclassification adjustments of other comprehensive income (loss) for the period, as those amounts, including amortization of the net transition asset or obligation, are recognized as components of net periodic benefit cost.",
        "label": "Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]",
        "terseLabel": "Schedule of Amounts Recognized in Other Comprehensive Income (Loss)"
       }
      }
     },
     "localname": "ScheduleOfAmountsRecognizedInOtherComprehensiveIncomeLossTableTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ScheduleOfAssumptionsUsedTableTextBlock": {
     "auth_ref": [
      "r283"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of assumption used to determine benefit obligation and net periodic benefit cost of defined benefit plan. Includes, but is not limited to, discount rate, rate of compensation increase, expected long-term rate of return on plan assets and interest crediting rate.",
        "label": "Defined Benefit Plan, Assumptions [Table Text Block]",
        "terseLabel": "Schedule of Assumptions Used"
       }
      }
     },
     "localname": "ScheduleOfAssumptionsUsedTableTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ScheduleOfCapitalUnitsTextBlock": {
     "auth_ref": [
      "r465"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of an entity's capital units or capital shares, including the value of capital units or capital shares, units authorized, units outstanding and other information necessary to a fair presentation.",
        "label": "Schedule of Capital Units [Table Text Block]",
        "terseLabel": "Schedule of Capital Stock"
       }
      }
     },
     "localname": "ScheduleOfCapitalUnitsTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/CapitalStockTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ScheduleOfChangesInProjectedBenefitObligationsTableTextBlock": {
     "auth_ref": [
      "r259"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of the change in the benefit obligation of pension plans and/or other employee benefit plans from the beginning to the end of the period, showing separately, if applicable, the effects of the following: service cost, interest cost, contributions by plan participants, actuarial gains and losses, foreign currency exchange rate changes, benefits paid, plan amendments, business combinations, divestitures, curtailments, settlements, and special and contractual termination benefits.",
        "label": "Schedule of Changes in Projected Benefit Obligations [Table Text Block]",
        "terseLabel": "Schedule of Accumulated and Projected Benefit Obligations"
       }
      }
     },
     "localname": "ScheduleOfChangesInProjectedBenefitObligationsTableTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock": {
     "auth_ref": [
      "r359"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of the components of income tax expense attributable to continuing operations for each year presented including, but not limited to: current tax expense (benefit), deferred tax expense (benefit), investment tax credits, government grants, the benefits of operating loss carryforwards, tax expense that results from allocating certain tax benefits either directly to contributed capital or to reduce goodwill or other noncurrent intangible assets of an acquired entity, adjustments of a deferred tax liability or asset for enacted changes in tax laws or rates or a change in the tax status of the entity, and adjustments of the beginning-of-the-year balances of a valuation allowance because of a change in circumstances that causes a change in judgment about the realizability of the related deferred tax asset in future years.",
        "label": "Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]",
        "terseLabel": "Schedule of Components of Income Tax Expense (Benefit)"
       }
      }
     },
     "localname": "ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ScheduleOfDebtInstrumentsTextBlock": {
     "auth_ref": [
      "r44",
      "r114",
      "r234",
      "r235",
      "r236",
      "r237",
      "r400",
      "r401",
      "r403",
      "r442"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.",
        "label": "Schedule of Long-term Debt Instruments [Table Text Block]",
        "terseLabel": "Schedule of Long-term Debt Instruments"
       }
      }
     },
     "localname": "ScheduleOfDebtInstrumentsTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock": {
     "auth_ref": [
      "r351"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of the components of net deferred tax asset or liability recognized in an entity's statement of financial position, including the following: the total of all deferred tax liabilities, the total of all deferred tax assets, the total valuation allowance recognized for deferred tax assets.",
        "label": "Schedule of Deferred Tax Assets and Liabilities [Table Text Block]",
        "terseLabel": "Schedule of Deferred Tax Assets and Liabilities"
       }
      }
     },
     "localname": "ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable": {
     "auth_ref": [
      "r288",
      "r289",
      "r290",
      "r291",
      "r298"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosures about an individual defined benefit pension plan or an other postretirement defined benefit plan. It may be appropriate to group certain similar plans.  Also includes schedule for fair value of plan assets by major categories of plan assets by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets or liabilities (Level 1), Significant other observable inputs (Level 2), and significant unobservable inputs (Level 3).",
        "label": "Schedule of Defined Benefit Plans Disclosures [Table]",
        "terseLabel": "Schedule of Defined Benefit Plans Disclosures [Table]"
       }
      }
     },
     "localname": "ScheduleOfDefinedBenefitPlansDisclosuresTable",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsDefinedContributionPlansDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock": {
     "auth_ref": [
      "r336"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of the reconciliation using percentage or dollar amounts of the reported amount of income tax expense attributable to continuing operations for the year to the amount of income tax expense that would result from applying domestic federal statutory tax rates to pretax income from continuing operations.",
        "label": "Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]",
        "terseLabel": "Reconciliation of Income Tax Statutory Rate"
       }
      }
     },
     "localname": "ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock": {
     "auth_ref": [
      "r274"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of benefits expected to be paid by pension plans and/or other employee benefit plans in each of the next five fiscal years and in the aggregate for the five fiscal years thereafter.",
        "label": "Schedule of Expected Benefit Payments [Table Text Block]",
        "terseLabel": "Schedule of Expected Benefit Payments"
       }
      }
     },
     "localname": "ScheduleOfExpectedBenefitPaymentsTableTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock": {
     "auth_ref": [
      "r192",
      "r195"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of assets, excluding financial assets and goodwill, lacking physical substance with a finite life, by either major class or business segment.",
        "label": "Schedule of Finite-Lived Intangible Assets [Table Text Block]",
        "terseLabel": "Schedule of Finite-Lived Intangible Assets by Major Class"
       }
      }
     },
     "localname": "ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ScheduleOfGoodwillTable": {
     "auth_ref": [
      "r187",
      "r189"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Schedule of goodwill and the changes during the year due to acquisition, sale, impairment or for other reasons.",
        "label": "Schedule of Goodwill [Table]",
        "terseLabel": "Schedule of Goodwill [Table]"
       }
      }
     },
     "localname": "ScheduleOfGoodwillTable",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsBalancesAndChangesInCarryingAmountsOfGoodwillDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_ScheduleOfGoodwillTextBlock": {
     "auth_ref": [
      "r187",
      "r189"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of goodwill by reportable segment and in total which includes a rollforward schedule.",
        "label": "Schedule of Goodwill [Table Text Block]",
        "terseLabel": "Schedule of Goodwill"
       }
      }
     },
     "localname": "ScheduleOfGoodwillTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock": {
     "auth_ref": [
      "r116"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of income before income tax between domestic and foreign jurisdictions.",
        "label": "Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]",
        "terseLabel": "Schedule of Income before Income Tax, Domestic and Foreign"
       }
      }
     },
     "localname": "ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock": {
     "auth_ref": [
      "r227"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of the combined aggregate amount of maturities and sinking fund requirements for all long-term borrowings for each of the five years following the date of the latest balance sheet date presented.",
        "label": "Schedule of Maturities of Long-term Debt [Table Text Block]",
        "terseLabel": "Schedule of Maturities of Long-term Debt"
       }
      }
     },
     "localname": "ScheduleOfMaturitiesOfLongTermDebtTableTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ScheduleOfNetBenefitCostsTableTextBlock": {
     "auth_ref": [
      "r275"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of the components of net benefit costs for pension plans and/or other employee benefit plans including service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) recognized due to settlements or curtailments.",
        "label": "Schedule of Net Benefit Costs [Table Text Block]",
        "terseLabel": "Schedule of Net Benefit Costs"
       }
      }
     },
     "localname": "ScheduleOfNetBenefitCostsTableTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/EmployeeBenefitsTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ScheduleOfPropertyPlantAndEquipmentTable": {
     "auth_ref": [
      "r34",
      "r209"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of information about physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, balances by class of assets, depreciation and depletion expense and method used, including composite depreciation, and accumulated deprecation.",
        "label": "Property, Plant and Equipment [Table]",
        "terseLabel": "Property, Plant and Equipment [Table]"
       }
      }
     },
     "localname": "ScheduleOfPropertyPlantAndEquipmentTable",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/PropertyBuildingsAndEquipmentDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_ScheduleOfQuarterlyFinancialInformationTableTextBlock": {
     "auth_ref": [
      "r133"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of quarterly financial data. Includes, but is not limited to, financial information for fiscal quarters, cumulative effect of a change in accounting principle and earnings per share data.",
        "label": "Quarterly Financial Information [Table Text Block]",
        "terseLabel": "Schedule of Quarterly Financial Information"
       }
      }
     },
     "localname": "ScheduleOfQuarterlyFinancialInformationTableTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SelectedQuarterlyFinancialDataUnauditedTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ScheduleOfRestructuringAndRelatedCostsTable": {
     "auth_ref": [
      "r217",
      "r218",
      "r220"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Table presenting the description of the restructuring costs, such as the expected cost; the costs incurred during the period; the cumulative costs incurred as of the balance sheet date; the income statement caption within which the restructuring charges recognized for the period are included; and the amount of and periodic changes to an entity's restructuring reserve that occurred during the period associated with the exit from or disposal of business activities or restructurings for each major type of cost by type of restructuring.",
        "label": "Schedule of Restructuring and Related Costs [Table]",
        "terseLabel": "Schedule of Restructuring and Related Costs [Table]"
       }
      }
     },
     "localname": "ScheduleOfRestructuringAndRelatedCostsTable",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable": {
     "auth_ref": [
      "r149",
      "r153",
      "r154",
      "r155",
      "r187"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "A table disclosing the profit or loss and total assets for each reportable segment of the entity. An entity discloses certain information on each reportable segment if the amounts (a) are included in the measure of segment profit or loss reviewed by the chief operating decision maker or (b) are otherwise regularly provided to the chief operating decision maker, even if not included in that measure of segment profit or loss.",
        "label": "Schedule of Segment Reporting Information, by Segment [Table]",
        "terseLabel": "Schedule of Segment Reporting Information, by Segment [Table]"
       }
      }
     },
     "localname": "ScheduleOfSegmentReportingInformationBySegmentTable",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsAdditionalInformationDetails",
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock": {
     "auth_ref": [
      "r149",
      "r153",
      "r154",
      "r155",
      "r187"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of the profit or loss and total assets for each reportable segment. An entity discloses certain information on each reportable segment if the amounts (a) are included in the measure of segment profit or loss reviewed by the chief operating decision maker or (b) are otherwise regularly provided to the chief operating decision maker, even if not included in that measure of segment profit or loss.",
        "label": "Schedule of Segment Reporting Information, by Segment [Table Text Block]",
        "terseLabel": "Summary of Segment Results"
       }
      }
     },
     "localname": "ScheduleOfSegmentReportingInformationBySegmentTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SegmentInformationTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable": {
     "auth_ref": [
      "r304",
      "r319"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of information about share-based payment arrangement.",
        "label": "Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]",
        "terseLabel": "Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]"
       }
      }
     },
     "localname": "ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansDetails",
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable": {
     "auth_ref": [
      "r319"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Details comprising a table providing supplementary information on outstanding and exercisable share awards as of the balance sheet date which stratifies outstanding options by ranges of exercise prices.",
        "label": "Share-based Payment Arrangement, Option, Exercise Price Range [Table]",
        "terseLabel": "Share-based Payment Arrangement, Option, Exercise Price Range [Table]"
       }
      }
     },
     "localname": "ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansStockOptionsOutstandingAndExercisableDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of the number and weighted-average grant date fair value for restricted stock and restricted stock units that were outstanding at the beginning and end of the year, and the number of restricted stock and restricted stock units that were granted, vested, or forfeited during the year.",
        "label": "Share-based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block]",
        "terseLabel": "Activity for restricted stock units"
       }
      }
     },
     "localname": "ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ScheduleOfShortTermDebtTable": {
     "auth_ref": [
      "r39"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "A table or schedule providing information pertaining to borrowings under which repayment was required in less than twelve months (or normal operating cycle, if longer) after its issuance. It may include: (1) description of the short-term debt arrangement; (2) identification of the lender or type of lender; (3) repayment terms; (4) weighted average interest rate; (5) carrying amount of funds borrowed under the specified short-term debt arrangement as of the balance sheet date and measures of the maximum and average amount outstanding during the period; (6) description of the refinancing of a short-term obligation when that obligation is excluded from current liabilities in the balance sheet; and (7) amount of a short-term obligation that has been excluded from current liabilities in the balance sheet because of a refinancing of the obligation.",
        "label": "Schedule of Short-term Debt [Table]",
        "terseLabel": "Schedule of Short-term Debt [Table]"
       }
      }
     },
     "localname": "ScheduleOfShortTermDebtTable",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ShortTermDebtDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_ScheduleOfShortTermDebtTextBlock": {
     "auth_ref": [
      "r39"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of short-term debt arrangements (having initial terms of repayment within one year or the normal operating cycle, if longer) including: (1) description of the short-term debt arrangement; (2) identification of the lender or type of lender; (3) repayment terms; (4) weighted average interest rate; (5) carrying amount of funds borrowed under the specified short-term debt arrangement as of the balance sheet date; (6) description of the refinancing of a short-term obligation when that obligation is excluded from current liabilities in the balance sheet; and (7) amount of a short-term obligation that has been excluded from current liabilities in the balance sheet because of a refinancing of the obligation.",
        "label": "Schedule of Short-term Debt [Table Text Block]",
        "terseLabel": "Schedule of Short-term Debt"
       }
      }
     },
     "localname": "ScheduleOfShortTermDebtTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ShortTermDebtTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock": {
     "auth_ref": [
      "r195"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of the amount of amortization expense expected to be recorded in succeeding fiscal years for finite-lived intangible assets.",
        "label": "Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]",
        "terseLabel": "Schedule of Estimated Amortization Expense"
       }
      }
     },
     "localname": "ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_SegmentDomain": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Components of an entity that engage in business activities from which they may earn revenue and incur expenses, including transactions with other components of the same entity.",
        "label": "Segments [Domain]",
        "terseLabel": "Segments [Domain]"
       }
      }
     },
     "localname": "SegmentDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsAdditionalInformationDetails",
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails",
      "http://www.grainger.com/role/RevenueDetails",
      "http://www.grainger.com/role/RevenueTables",
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_SegmentReportingAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Segment Reporting [Abstract]"
       }
      }
     },
     "localname": "SegmentReportingAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "xbrltype": "stringItemType"
    },
    "us-gaap_SegmentReportingDisclosureTextBlock": {
     "auth_ref": [
      "r163"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.",
        "label": "Segment Reporting Disclosure [Text Block]",
        "terseLabel": "SEGMENT INFORMATION"
       }
      }
     },
     "localname": "SegmentReportingDisclosureTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SegmentInformation"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_SegmentReportingInformationLineItems": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.",
        "label": "Segment Reporting Information [Line Items]",
        "terseLabel": "Segment Reporting Information [Line Items]"
       }
      }
     },
     "localname": "SegmentReportingInformationLineItems",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsAdditionalInformationDetails",
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_SellingGeneralAndAdministrativeExpense": {
     "auth_ref": [
      "r78",
      "r174"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings": {
       "order": 2.0,
       "parentTag": "us-gaap_OperatingIncomeLoss",
       "weight": -1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The aggregate total costs related to selling a firm's product and services, as well as all other general and administrative expenses. Direct selling expenses (for example, credit, warranty, and advertising) are expenses that can be directly linked to the sale of specific products. Indirect selling expenses are expenses that cannot be directly linked to the sale of specific products, for example telephone expenses, Internet, and postal charges. General and administrative expenses include salaries of non-sales personnel, rent, utilities, communication, etc.",
        "label": "Selling, General and Administrative Expense",
        "verboseLabel": "Selling, general and administrative expenses"
       }
      }
     },
     "localname": "SellingGeneralAndAdministrativeExpense",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings",
      "http://www.grainger.com/role/SelectedQuarterlyFinancialDataUnauditedDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_SellingGeneralAndAdministrativeExpensesMember": {
     "auth_ref": [
      "r81"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Primary financial statement caption encompassing selling, general and administrative expense.",
        "label": "Selling, General and Administrative Expenses [Member]",
        "terseLabel": "Selling, General and Administrative Expenses [Member]"
       }
      }
     },
     "localname": "SellingGeneralAndAdministrativeExpensesMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_SellingGeneralAndAdministrativeExpensesPolicyTextBlock": {
     "auth_ref": [
      "r108",
      "r324"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of accounting policy for inclusion of significant items in the selling, general and administrative (or similar) expense report caption.",
        "label": "Selling, General and Administrative Expenses, Policy [Policy Text Block]",
        "terseLabel": "SELLING, GENERAL AND ADMINISTRATIVE EXPENSES"
       }
      }
     },
     "localname": "SellingGeneralAndAdministrativeExpensesPolicyTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_SeniorNotesMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Bond that takes priority over other debt securities sold by the issuer. In the event the issuer goes bankrupt, senior debt holders receive priority for (must receive) repayment prior to (relative to) junior and unsecured (general) creditors.",
        "label": "Senior Notes [Member]",
        "terseLabel": "Senior notes [Member]"
       }
      }
     },
     "localname": "SeniorNotesMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails",
      "http://www.grainger.com/role/LongTermDebtScheduleOfLongTermDebtDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_ShareBasedCompensation": {
     "auth_ref": [
      "r101"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows": {
       "order": 7.0,
       "parentTag": "us-gaap_NetCashProvidedByUsedInOperatingActivities",
       "weight": 1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of noncash expense for share-based payment arrangement.",
        "label": "Share-based Payment Arrangement, Noncash Expense",
        "terseLabel": "Stock-based compensation"
       }
      }
     },
     "localname": "ShareBasedCompensation",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1": {
     "auth_ref": [
      "r305"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.",
        "label": "Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period",
        "terseLabel": "Award vesting period"
       }
      }
     },
     "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansDetails",
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails"
     ],
     "xbrltype": "durationItemType"
    },
    "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod": {
     "auth_ref": [
      "r310"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.",
        "label": "Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period",
        "negatedTerseLabel": "Canceled (in shares)"
       }
      }
     },
     "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails"
     ],
     "xbrltype": "sharesItemType"
    },
    "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue": {
     "auth_ref": [
      "r314"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.",
        "label": "Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value",
        "terseLabel": "Cancelled, weighted average price per share (in dollars per share)"
       }
      }
     },
     "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails"
     ],
     "xbrltype": "perShareItemType"
    },
    "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod": {
     "auth_ref": [
      "r312"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).",
        "label": "Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period",
        "terseLabel": "Issued (in shares)"
       }
      }
     },
     "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails"
     ],
     "xbrltype": "sharesItemType"
    },
    "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue": {
     "auth_ref": [
      "r312"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).",
        "label": "Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value",
        "terseLabel": "Issued, weighted average price per share (in dollars per share)"
       }
      }
     },
     "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails"
     ],
     "xbrltype": "perShareItemType"
    },
    "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber": {
     "auth_ref": [
      "r311"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.",
        "label": "Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number",
        "periodEndLabel": "Outstanding at end of period (in shares)",
        "periodStartLabel": "Outstanding at beginning of period (in shares)"
       }
      }
     },
     "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails"
     ],
     "xbrltype": "sharesItemType"
    },
    "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.",
        "label": "Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]",
        "terseLabel": "Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]"
       }
      }
     },
     "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue": {
     "auth_ref": [
      "r311"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.",
        "label": "Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value",
        "periodEndLabel": "Outstanding at end of period, weighted average price per share (in dollars per share)",
        "periodStartLabel": "Outstanding at beginning of period, weighted average price per share (in dollars per share)"
       }
      }
     },
     "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails"
     ],
     "xbrltype": "perShareItemType"
    },
    "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod": {
     "auth_ref": [
      "r313"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.",
        "label": "Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period",
        "negatedTerseLabel": "Vested (in shares)"
       }
      }
     },
     "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails"
     ],
     "xbrltype": "sharesItemType"
    },
    "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue": {
     "auth_ref": [
      "r313"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.",
        "label": "Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value",
        "terseLabel": "Vested, weighted average price per share (in dollars per share)"
       }
      }
     },
     "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails"
     ],
     "xbrltype": "perShareItemType"
    },
    "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.",
        "label": "Share-based Compensation Arrangement by Share-based Payment Award [Line Items]",
        "terseLabel": "Share-based Compensation Arrangement by Share-based Payment Award [Line Items]"
       }
      }
     },
     "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansDetails",
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant": {
     "auth_ref": [
      "r319"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.",
        "label": "Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant",
        "terseLabel": "Shares of common stock available for grant under stock incentive plans (in shares)"
       }
      }
     },
     "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansDetails"
     ],
     "xbrltype": "sharesItemType"
    },
    "us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.",
        "label": "Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]",
        "terseLabel": "Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]"
       }
      }
     },
     "localname": "ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain": {
     "auth_ref": [
      "r302",
      "r307"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Award under share-based payment arrangement.",
        "label": "Award Type [Domain]",
        "terseLabel": "Award Type [Domain]"
       }
      }
     },
     "localname": "ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansDetails",
      "http://www.grainger.com/role/StockIncentivePlansRestrictedStockUnitsDetails",
      "http://www.grainger.com/role/StockIncentivePlansStockOptionsOutstandingAndExercisableDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy": {
     "auth_ref": [
      "r108",
      "r304",
      "r308"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of accounting policy for award under share-based payment arrangement. Includes, but is not limited to, methodology and assumption used in measuring cost.",
        "label": "Share-based Payment Arrangement [Policy Text Block]",
        "terseLabel": "STOCK INCENTIVE PLANS"
       }
      }
     },
     "localname": "ShareBasedCompensationOptionAndIncentivePlansPolicy",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis": {
     "auth_ref": [
      "r315"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by range of option prices pertaining to options granted.",
        "label": "Exercise Price Range [Axis]",
        "terseLabel": "Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Axis]"
       }
      }
     },
     "localname": "ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansStockOptionsOutstandingAndExercisableDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain": {
     "auth_ref": [
      "r316"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Supplementary information on outstanding and exercisable share awards as of the balance sheet date which stratifies outstanding options by ranges of exercise prices.",
        "label": "Exercise Price Range [Domain]",
        "terseLabel": "Exercise Price Range [Domain]"
       }
      }
     },
     "localname": "ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansStockOptionsOutstandingAndExercisableDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.",
        "label": "Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]",
        "terseLabel": "Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]"
       }
      }
     },
     "localname": "ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansStockOptionsOutstandingAndExercisableDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod": {
     "auth_ref": [
      "r306"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.",
        "label": "Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period",
        "terseLabel": "Expiration period"
       }
      }
     },
     "localname": "SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansDetails"
     ],
     "xbrltype": "durationItemType"
    },
    "us-gaap_ShortTermBorrowings": {
     "auth_ref": [
      "r13",
      "r429",
      "r450"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 1.0,
       "parentTag": "us-gaap_LiabilitiesCurrent",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.",
        "label": "Short-term Debt",
        "terseLabel": "Short-term debt",
        "verboseLabel": "Short-term debt, outstanding"
       }
      }
     },
     "localname": "ShortTermBorrowings",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets",
      "http://www.grainger.com/role/ShortTermDebtDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_ShortTermBorrowingsAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Short-term Debt [Abstract]"
       }
      }
     },
     "localname": "ShortTermBorrowingsAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "xbrltype": "stringItemType"
    },
    "us-gaap_ShortTermDebtLineItems": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.",
        "label": "Short-term Debt [Line Items]",
        "terseLabel": "Short-term Debt [Line Items]"
       }
      }
     },
     "localname": "ShortTermDebtLineItems",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ShortTermDebtDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_ShortTermDebtTextBlock": {
     "auth_ref": [
      "r232"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The entire disclosure for short-term debt.",
        "label": "Short-term Debt [Text Block]",
        "terseLabel": "SHORT-TERM DEBT"
       }
      }
     },
     "localname": "ShortTermDebtTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ShortTermDebt"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ShortTermDebtTypeAxis": {
     "auth_ref": [
      "r39"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by type of short-term debt arrangement.",
        "label": "Short-term Debt, Type [Axis]",
        "terseLabel": "Short-term Debt, Type [Axis]"
       }
      }
     },
     "localname": "ShortTermDebtTypeAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ShortTermDebtDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_ShortTermDebtTypeDomain": {
     "auth_ref": [
      "r36"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Type of short-term debt arrangement, such as notes, line of credit, commercial paper, asset-based financing, project financing, letter of credit financing.",
        "label": "Short-term Debt, Type [Domain]",
        "terseLabel": "Short-term Debt, Type [Domain]"
       }
      }
     },
     "localname": "ShortTermDebtTypeDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ShortTermDebtDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_ShortTermDebtWeightedAverageInterestRate": {
     "auth_ref": [
      "r37"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Weighted average interest rate of short-term debt outstanding calculated at point in time.",
        "label": "Short-term Debt, Weighted Average Interest Rate, at Point in Time",
        "terseLabel": "Weighted average interest rate at December 31"
       }
      }
     },
     "localname": "ShortTermDebtWeightedAverageInterestRate",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ShortTermDebtDetails"
     ],
     "xbrltype": "percentItemType"
    },
    "us-gaap_ShorttermDebtMaximumMonthendOutstandingAmount": {
     "auth_ref": [
      "r14"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, maximum month-end borrowings during the period.",
        "label": "Short-term Debt, Maximum Month-end Outstanding Amount",
        "terseLabel": "Maximum month-end balance during the year"
       }
      }
     },
     "localname": "ShorttermDebtMaximumMonthendOutstandingAmount",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ShortTermDebtDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_SignificantAccountingPoliciesTextBlock": {
     "auth_ref": [
      "r121"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The entire disclosure for all significant accounting policies of the reporting entity.",
        "label": "Significant Accounting Policies [Text Block]",
        "terseLabel": "SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES"
       }
      }
     },
     "localname": "SignificantAccountingPoliciesTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_SoftwareAndSoftwareDevelopmentCostsMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Purchased software applications and internally developed software for sale, licensing or long-term internal use.",
        "label": "Software and Software Development Costs [Member]",
        "terseLabel": "Capitalized software [Member]"
       }
      }
     },
     "localname": "SoftwareAndSoftwareDevelopmentCostsMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_StatementBusinessSegmentsAxis": {
     "auth_ref": [
      "r0",
      "r153",
      "r187",
      "r212",
      "r216",
      "r221",
      "r460"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by business segments.",
        "label": "Segments [Axis]",
        "terseLabel": "Segments [Axis]"
       }
      }
     },
     "localname": "StatementBusinessSegmentsAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsAdditionalInformationDetails",
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails",
      "http://www.grainger.com/role/RevenueDetails",
      "http://www.grainger.com/role/RevenueTables",
      "http://www.grainger.com/role/SegmentInformationDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_StatementEquityComponentsAxis": {
     "auth_ref": [
      "r46",
      "r233"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by component of equity.",
        "label": "Equity Components [Axis]",
        "terseLabel": "Equity Components [Axis]"
       }
      }
     },
     "localname": "StatementEquityComponentsAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails",
      "http://www.grainger.com/role/CapitalStockDetails",
      "http://www.grainger.com/role/ConsolidatedStatementsOfShareholdersEquity",
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_StatementLineItems": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.",
        "label": "Statement [Line Items]",
        "terseLabel": "Statement [Line Items]"
       }
      }
     },
     "localname": "StatementLineItems",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/CapitalStockDetails",
      "http://www.grainger.com/role/ConsolidatedStatementsOfShareholdersEquity",
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails",
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails",
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_StatementOfCashFlowsAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Statement of Cash Flows [Abstract]"
       }
      }
     },
     "localname": "StatementOfCashFlowsAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "xbrltype": "stringItemType"
    },
    "us-gaap_StatementOfFinancialPositionAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Statement of Financial Position [Abstract]"
       }
      }
     },
     "localname": "StatementOfFinancialPositionAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "xbrltype": "stringItemType"
    },
    "us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Statement of Comprehensive Income [Abstract]"
       }
      }
     },
     "localname": "StatementOfIncomeAndComprehensiveIncomeAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "xbrltype": "stringItemType"
    },
    "us-gaap_StatementOfStockholdersEquityAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Statement of Stockholders' Equity [Abstract]"
       }
      }
     },
     "localname": "StatementOfStockholdersEquityAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "xbrltype": "stringItemType"
    },
    "us-gaap_StatementTable": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Schedule reflecting a Statement of Income, Statement of Cash Flows, Statement of Financial Position, Statement of Shareholders' Equity and Other Comprehensive Income, or other statement as needed.",
        "label": "Statement [Table]",
        "terseLabel": "Statement [Table]"
       }
      }
     },
     "localname": "StatementTable",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/CapitalStockDetails",
      "http://www.grainger.com/role/ConsolidatedStatementsOfShareholdersEquity",
      "http://www.grainger.com/role/EmployeeBenefitsPostretirementBenefitsDetails",
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails",
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross": {
     "auth_ref": [
      "r233",
      "r238"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Total number of shares issued during the period, including shares forfeited, as a result of Restricted Stock Awards.",
        "label": "Stock Issued During Period, Shares, Restricted Stock Award, Gross",
        "terseLabel": "Settlement of restricted stock units, net of 26,107, 39,075 and 36,585 shares retained, respectively (in shares)"
       }
      }
     },
     "localname": "StockIssuedDuringPeriodSharesRestrictedStockAwardGross",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/CapitalStockDetails"
     ],
     "xbrltype": "sharesItemType"
    },
    "us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised": {
     "auth_ref": [
      "r20",
      "r21",
      "r233",
      "r238",
      "r309"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Number of share options (or share units) exercised during the current period.",
        "label": "Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period",
        "negatedTerseLabel": "Exercised (in shares)",
        "terseLabel": "Exercise of stock options (in shares)"
       }
      }
     },
     "localname": "StockIssuedDuringPeriodSharesStockOptionsExercised",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/CapitalStockDetails",
      "http://www.grainger.com/role/StockIncentivePlansDetails"
     ],
     "xbrltype": "sharesItemType"
    },
    "us-gaap_StockOptionPlanExpense": {
     "auth_ref": [
      "r102"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of noncash expense for option under share-based payment arrangement.",
        "label": "Stock or Unit Option Plan Expense",
        "terseLabel": "Stock or Unit Option Plan Expense"
       }
      }
     },
     "localname": "StockOptionPlanExpense",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/StockIncentivePlansStockOptionsOutstandingAndExercisableDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_StockRepurchasedDuringPeriodValue": {
     "auth_ref": [
      "r20",
      "r21",
      "r233",
      "r238"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.",
        "label": "Stock Repurchased During Period, Value",
        "negatedTerseLabel": "Purchases of treasury stock"
       }
      }
     },
     "localname": "StockRepurchasedDuringPeriodValue",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfShareholdersEquity"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_StockholdersEquity": {
     "auth_ref": [
      "r21",
      "r25",
      "r26",
      "r168"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 1.0,
       "parentTag": "us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.",
        "label": "Stockholders' Equity Attributable to Parent",
        "totalLabel": "Total W.W. Grainger, Inc. shareholders\u2019 equity"
       }
      }
     },
     "localname": "StockholdersEquity",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest": {
     "auth_ref": [
      "r369",
      "r370",
      "r382"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 5.0,
       "parentTag": "us-gaap_LiabilitiesAndStockholdersEquity",
       "weight": 1.0
      }
     },
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity.",
        "label": "Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest",
        "periodEndLabel": "Ending balance",
        "periodStartLabel": "Beginning balance",
        "totalLabel": "Total shareholders' equity"
       }
      }
     },
     "localname": "StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/AccumulatedOtherComprehensiveEarningsLossesAoceDetails",
      "http://www.grainger.com/role/ConsolidatedBalanceSheets",
      "http://www.grainger.com/role/ConsolidatedStatementsOfShareholdersEquity"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]",
        "terseLabel": "SHAREHOLDERS' EQUITY"
       }
      }
     },
     "localname": "StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_StockholdersEquityNoteAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Stockholders' Equity Note [Abstract]"
       }
      }
     },
     "localname": "StockholdersEquityNoteAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "xbrltype": "stringItemType"
    },
    "us-gaap_SubsequentEventLineItems": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.",
        "label": "Subsequent Event [Line Items]",
        "terseLabel": "Subsequent Event [Line Items]"
       }
      }
     },
     "localname": "SubsequentEventLineItems",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SubsequentEventDetails",
      "http://www.grainger.com/role/SubsequentEventNotes"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_SubsequentEventMember": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Identifies event that occurred after the balance sheet date but before financial statements are issued or available to be issued.",
        "label": "Subsequent Event [Member]",
        "terseLabel": "Subsequent Event [Member]"
       }
      }
     },
     "localname": "SubsequentEventMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SubsequentEventDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_SubsequentEventTable": {
     "auth_ref": [
      "r420"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Discloses pertinent information about one or more significant events or transactions that occurred after the balance sheet date through the date the financial statements were issued or the date the financial statements were available to be issued.",
        "label": "Subsequent Event [Table]",
        "terseLabel": "Subsequent Event [Table]"
       }
      }
     },
     "localname": "SubsequentEventTable",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SubsequentEventDetails",
      "http://www.grainger.com/role/SubsequentEventNotes"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_SubsequentEventTypeAxis": {
     "auth_ref": [
      "r420"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by event that occurred after the balance sheet date but before financial statements are issued or available to be issued.",
        "label": "Subsequent Event Type [Axis]",
        "terseLabel": "Subsequent Event Type [Axis]"
       }
      }
     },
     "localname": "SubsequentEventTypeAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SubsequentEventDetails",
      "http://www.grainger.com/role/SubsequentEventNotes"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_SubsequentEventTypeDomain": {
     "auth_ref": [
      "r420"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Event that occurred after the balance sheet date but before financial statements are issued or available to be issued.",
        "label": "Subsequent Event Type [Domain]",
        "terseLabel": "Subsequent Event Type [Domain]"
       }
      }
     },
     "localname": "SubsequentEventTypeDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SubsequentEventDetails",
      "http://www.grainger.com/role/SubsequentEventNotes"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_SubsequentEventsAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Subsequent Events [Abstract]"
       }
      }
     },
     "localname": "SubsequentEventsAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "xbrltype": "stringItemType"
    },
    "us-gaap_SubsequentEventsTextBlock": {
     "auth_ref": [
      "r422"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The entire disclosure for significant events or transactions that occurred after the balance sheet date through the date the financial statements were issued or the date the financial statements were available to be issued. Examples include: the sale of a capital stock issue, purchase of a business, settlement of litigation, catastrophic loss, significant foreign exchange rate changes, loans to insiders or affiliates, and transactions not in the ordinary course of business.",
        "label": "Subsequent Events [Text Block]",
        "terseLabel": "Subsequent Events [Text Block]"
       }
      }
     },
     "localname": "SubsequentEventsTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SubsequentEventNotes"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_SummaryOfIncomeTaxContingenciesTextBlock": {
     "auth_ref": [
      "r338",
      "r344",
      "r346"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure for tax positions taken in the tax returns filed or to be filed for which it is more likely than not that the tax position will not be sustained upon examination by taxing authorities and other income tax contingencies. Includes, but is not limited to, interest and penalties, reconciliation of unrecognized tax benefits, unrecognized tax benefits that would affect the effective tax rate, tax years that remain subject to examination by tax jurisdictions, and information about positions for which it is reasonably possible that amounts unrecognized will significantly change within 12 months.",
        "label": "Summary of Income Tax Contingencies [Table Text Block]",
        "terseLabel": "Reconciliation of Income Tax Contingencies"
       }
      }
     },
     "localname": "SummaryOfIncomeTaxContingenciesTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_SummaryOfValuationAllowanceTextBlock": {
     "auth_ref": [
      "r350"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Tabular disclosure of valuation allowances to reduce deferred tax assets to net realizable value, including identification of the deferred tax asset more likely than not will not be fully realized and the corresponding amount of the valuation allowance.",
        "label": "Summary of Valuation Allowance [Table Text Block]",
        "terseLabel": "Summary of Valuation Allowance Changes"
       }
      }
     },
     "localname": "SummaryOfValuationAllowanceTextBlock",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesTables"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_SupplementalCashFlowInformationAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Supplemental Cash Flow Information [Abstract]",
        "terseLabel": "Supplemental cash flow information:"
       }
      }
     },
     "localname": "SupplementalCashFlowInformationAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfCashFlows"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_TimingOfTransferOfGoodOrServiceAxis": {
     "auth_ref": [
      "r251"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by timing of transfer of good or service to customer.",
        "label": "Timing of Transfer of Good or Service [Axis]",
        "terseLabel": "Timing of Transfer of Good or Service [Axis]"
       }
      }
     },
     "localname": "TimingOfTransferOfGoodOrServiceAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails",
      "http://www.grainger.com/role/RevenueTables"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_TimingOfTransferOfGoodOrServiceDomain": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Timing of transfer of good or service to customer. Includes, but is not limited to, at point in time or over time.",
        "label": "Timing of Transfer of Good or Service [Domain]",
        "terseLabel": "Timing of Transfer of Good or Service [Domain]"
       }
      }
     },
     "localname": "TimingOfTransferOfGoodOrServiceDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RevenueDetails",
      "http://www.grainger.com/role/RevenueTables"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_TrademarksAndTradeNamesMember": {
     "auth_ref": [
      "r368"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Rights acquired through registration of a trademark to gain or protect exclusive use of a business name, symbol or other device or style, or rights either acquired through registration of a business name to gain or protect exclusive use thereof.",
        "label": "Trademarks and Trade Names [Member]",
        "terseLabel": "Trademarks, trade names and other [Member]"
       }
      }
     },
     "localname": "TrademarksAndTradeNamesMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/GoodwillAndOtherIntangibleAssetsIntangibleAssetsIncludedInOtherAssetsAndIntangiblesDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_TreasuryStockMember": {
     "auth_ref": [
      "r45",
      "r240"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Shares of an entity that have been repurchased by the entity. This stock has no voting rights and receives no dividends. Note that treasury stock may be recorded at its total cost or separately as par (or stated) value and additional paid in capital. Classified within stockholders' equity if nonredeemable or redeemable solely at the option of the issuer. Classified within temporary equity if redemption is outside the control of the issuer.",
        "label": "Treasury Stock [Member]",
        "terseLabel": "Treasury Stock [Member]"
       }
      }
     },
     "localname": "TreasuryStockMember",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/CapitalStockDetails",
      "http://www.grainger.com/role/ConsolidatedStatementsOfShareholdersEquity"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_TreasuryStockShares": {
     "auth_ref": [
      "r45",
      "r240"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends.",
        "label": "Treasury Stock, Shares",
        "periodEndLabel": "Balance at end of period, treasury stock (in shares)",
        "periodStartLabel": "Balance at beginning of period, treasury stock (in shares)",
        "terseLabel": "Treasury stock, shares at cost (in shares)"
       }
      }
     },
     "localname": "TreasuryStockShares",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/CapitalStockDetails",
      "http://www.grainger.com/role/ConsolidatedBalanceSheetsParentheticals"
     ],
     "xbrltype": "sharesItemType"
    },
    "us-gaap_TreasuryStockSharesAcquired": {
     "auth_ref": [
      "r21",
      "r233",
      "r238"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Number of shares that have been repurchased during the period and are being held in treasury.",
        "label": "Treasury Stock, Shares, Acquired",
        "terseLabel": "Purchase of treasury shares (in shares)"
       }
      }
     },
     "localname": "TreasuryStockSharesAcquired",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/CapitalStockDetails"
     ],
     "xbrltype": "sharesItemType"
    },
    "us-gaap_TreasuryStockValue": {
     "auth_ref": [
      "r45",
      "r240",
      "r241"
     ],
     "calculation": {
      "http://www.grainger.com/role/ConsolidatedBalanceSheets": {
       "order": 6.0,
       "parentTag": "us-gaap_StockholdersEquity",
       "weight": -1.0
      }
     },
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The amount allocated to treasury stock. Treasury stock is common and preferred shares of an entity that were issued, repurchased by the entity, and are held in its treasury.",
        "label": "Treasury Stock, Value",
        "negatedLabel": "Treasury stock, at cost - 55,971,691 and 53,796,859 shares, respectively"
       }
      }
     },
     "localname": "TreasuryStockValue",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedBalanceSheets"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_TypeOfRestructuringDomain": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Identification of the types of restructuring costs.",
        "label": "Type of Restructuring [Domain]",
        "terseLabel": "Type of Restructuring [Domain]"
       }
      }
     },
     "localname": "TypeOfRestructuringDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/RestructuringReservesRestructuringDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_UndistributedEarningsOfForeignSubsidiaries": {
     "auth_ref": [
      "r329",
      "r363",
      "r443",
      "r464"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of undistributed earnings of foreign subsidiaries intended to be permanently reinvested outside the country of domicile.",
        "label": "Undistributed Earnings of Foreign Subsidiaries",
        "terseLabel": "Undistributed earnings of foreign subsidiaries"
       }
      }
     },
     "localname": "UndistributedEarningsOfForeignSubsidiaries",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_UnrecognizedTaxBenefits": {
     "auth_ref": [
      "r330",
      "r339"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of unrecognized tax benefits.",
        "label": "Unrecognized Tax Benefits",
        "periodEndLabel": "Balance at end of year",
        "periodStartLabel": "Balance at beginning of year"
       }
      }
     },
     "localname": "UnrecognizedTaxBenefits",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesChangesInLiabilityForTaxUncertaintiesExcludingInterestDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions": {
     "auth_ref": [
      "r340"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.",
        "label": "Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions",
        "negatedTerseLabel": "Reductions for tax positions of prior years"
       }
      }
     },
     "localname": "UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesChangesInLiabilityForTaxUncertaintiesExcludingInterestDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities": {
     "auth_ref": [
      "r342"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.",
        "label": "Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities",
        "negatedTerseLabel": "Settlements, audit payments, refunds - net"
       }
      }
     },
     "localname": "UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesChangesInLiabilityForTaxUncertaintiesExcludingInterestDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions": {
     "auth_ref": [
      "r341"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.",
        "label": "Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions",
        "terseLabel": "Additions for tax positions related to the current year"
       }
      }
     },
     "localname": "UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesChangesInLiabilityForTaxUncertaintiesExcludingInterestDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions": {
     "auth_ref": [
      "r340"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.",
        "label": "Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions",
        "terseLabel": "Additions for tax positions of prior years"
       }
      }
     },
     "localname": "UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesChangesInLiabilityForTaxUncertaintiesExcludingInterestDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations": {
     "auth_ref": [
      "r343"
     ],
     "crdr": "debit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.",
        "label": "Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations",
        "negatedTerseLabel": "Reductions due to statute lapse"
       }
      }
     },
     "localname": "UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesChangesInLiabilityForTaxUncertaintiesExcludingInterestDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_UseOfEstimates": {
     "auth_ref": [
      "r135",
      "r136",
      "r138",
      "r139",
      "r140",
      "r141",
      "r142"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Disclosure of accounting policy for the use of estimates in the preparation of financial statements in conformity with generally accepted accounting principles.",
        "label": "Use of Estimates, Policy [Policy Text Block]",
        "terseLabel": "USE OF ESTIMATES"
       }
      }
     },
     "localname": "UseOfEstimates",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/SummaryOfSignificantAccountingPoliciesPolicies"
     ],
     "xbrltype": "textBlockItemType"
    },
    "us-gaap_ValuationAllowanceByDeferredTaxAssetAxis": {
     "auth_ref": [
      "r350"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by type of deferred tax consequences attributable to deductible temporary differences.",
        "label": "Valuation Allowance by Deferred Tax Asset [Axis]",
        "terseLabel": "Valuation Allowance by Deferred Tax Asset [Axis]"
       }
      }
     },
     "localname": "ValuationAllowanceByDeferredTaxAssetAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesChangesInValuationAllowanceDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount": {
     "auth_ref": [
      "r331"
     ],
     "crdr": "credit",
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Amount of increase (decrease) in the valuation allowance for a specified deferred tax asset.",
        "label": "Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount",
        "terseLabel": "Valuation allowance, increase (decrease)"
       }
      }
     },
     "localname": "ValuationAllowanceDeferredTaxAssetChangeInAmount",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesChangesInValuationAllowanceDetails"
     ],
     "xbrltype": "monetaryItemType"
    },
    "us-gaap_ValuationAllowanceLineItems": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.",
        "label": "Valuation Allowance [Line Items]",
        "terseLabel": "Valuation Allowance [Line Items]"
       }
      }
     },
     "localname": "ValuationAllowanceLineItems",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesChangesInValuationAllowanceDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_ValuationAllowanceTable": {
     "auth_ref": [
      "r350"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "A listing of an entity's valuation allowances to reduce deferred tax assets to amounts which it is more likely than not will not be realized, including a description of the deferred tax assets for which the valuation allowance has been recorded and the amount of the valuation allowance.",
        "label": "Valuation Allowance [Table]",
        "terseLabel": "Valuation Allowance [Table]"
       }
      }
     },
     "localname": "ValuationAllowanceTable",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/IncomeTaxesChangesInValuationAllowanceDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_VariableRateAxis": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Information by type of variable rate.",
        "label": "Variable Rate [Axis]",
        "terseLabel": "Variable Rate [Axis]"
       }
      }
     },
     "localname": "VariableRateAxis",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_VariableRateDomain": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Interest rate that fluctuates over time as a result of an underlying benchmark interest rate or index.",
        "label": "Variable Rate [Domain]",
        "terseLabel": "Variable Rate [Domain]"
       }
      }
     },
     "localname": "VariableRateDomain",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/LongTermDebtDetails"
     ],
     "xbrltype": "domainItemType"
    },
    "us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding": {
     "auth_ref": [
      "r125",
      "r129"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.",
        "label": "Weighted Average Number of Shares Outstanding, Diluted",
        "terseLabel": "Diluted (in shares)"
       }
      }
     },
     "localname": "WeightedAverageNumberOfDilutedSharesOutstanding",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings"
     ],
     "xbrltype": "sharesItemType"
    },
    "us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract": {
     "auth_ref": [],
     "lang": {
      "en-US": {
       "role": {
        "label": "Weighted Average Number of Shares Outstanding, Diluted [Abstract]",
        "terseLabel": "Weighted average number of shares outstanding:"
       }
      }
     },
     "localname": "WeightedAverageNumberOfSharesOutstandingAbstract",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings"
     ],
     "xbrltype": "stringItemType"
    },
    "us-gaap_WeightedAverageNumberOfSharesOutstandingBasic": {
     "auth_ref": [
      "r124",
      "r129"
     ],
     "lang": {
      "en-US": {
       "role": {
        "documentation": "Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.",
        "label": "Weighted Average Number of Shares Outstanding, Basic",
        "terseLabel": "Basic (in shares)"
       }
      }
     },
     "localname": "WeightedAverageNumberOfSharesOutstandingBasic",
     "nsuri": "http://fasb.org/us-gaap/2019-01-31",
     "presentation": [
      "http://www.grainger.com/role/ConsolidatedStatementsOfEarnings"
     ],
     "xbrltype": "sharesItemType"
    }
   },
   "unitCount": 9
  }
 },
 "std_ref": {
  "r0": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(d)",
   "Topic": "205",
   "URI": "http://asc.fasb.org/extlink&oid=109222650&loc=d3e1361-107760"
  },
  "r1": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(a)",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=118951113&loc=d3e6676-107765"
  },
  "r10": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(13))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r100": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "25",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3536-108585"
  },
  "r101": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "28",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(a)",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585"
  },
  "r102": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "28",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585"
  },
  "r103": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "28",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585"
  },
  "r104": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3044-108585"
  },
  "r105": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "9",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(c)",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3098-108585"
  },
  "r106": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=98513485&loc=d3e4273-108586"
  },
  "r107": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=98513485&loc=d3e4297-108586"
  },
  "r108": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "235",
   "URI": "http://asc.fasb.org/extlink&oid=84158767&loc=d3e18780-107790"
  },
  "r109": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(e)",
   "Topic": "235",
   "URI": "http://asc.fasb.org/extlink&oid=84158767&loc=d3e18823-107790"
  },
  "r11": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(14))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r110": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(f)",
   "Topic": "235",
   "URI": "http://asc.fasb.org/extlink&oid=84158767&loc=d3e18823-107790"
  },
  "r111": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.4-08(h)(1))",
   "Topic": "235",
   "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690"
  },
  "r112": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.4-08(h)(2))",
   "Topic": "235",
   "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690"
  },
  "r113": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.4-08(h))",
   "Topic": "235",
   "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690"
  },
  "r114": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.4-08.(e),(f))",
   "Topic": "235",
   "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690"
  },
  "r115": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.4-08.(f))",
   "Topic": "235",
   "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690"
  },
  "r116": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.4-08.(h)(1)(i))",
   "Topic": "235",
   "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690"
  },
  "r117": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.4-08.(h)(2))",
   "Topic": "235",
   "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690"
  },
  "r118": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.4-08.(h))",
   "Topic": "235",
   "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690"
  },
  "r119": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.12-04(a))",
   "Topic": "235",
   "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690"
  },
  "r12": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(19)(a)(3))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r120": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.12-04.(a))",
   "Topic": "235",
   "URI": "http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690"
  },
  "r121": {
   "Name": "Accounting Standards Codification",
   "Publisher": "FASB",
   "Topic": "235",
   "URI": "http://asc.fasb.org/topic&trid=2122369"
  },
  "r122": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "250",
   "URI": "http://asc.fasb.org/extlink&oid=109234566&loc=d3e22499-107794"
  },
  "r123": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "11",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "250",
   "URI": "http://asc.fasb.org/extlink&oid=109234566&loc=d3e22694-107794"
  },
  "r124": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "10",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "260",
   "URI": "http://asc.fasb.org/extlink&oid=117326831&loc=d3e1448-109256"
  },
  "r125": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "16",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "260",
   "URI": "http://asc.fasb.org/extlink&oid=117326831&loc=d3e1505-109256"
  },
  "r126": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "260",
   "URI": "http://asc.fasb.org/extlink&oid=117326831&loc=d3e1252-109256"
  },
  "r127": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "60B",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(d)",
   "Topic": "260",
   "URI": "http://asc.fasb.org/extlink&oid=117326831&loc=SL5780133-109256"
  },
  "r128": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "7",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "260",
   "URI": "http://asc.fasb.org/extlink&oid=117326831&loc=d3e1337-109256"
  },
  "r129": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a)",
   "Topic": "260",
   "URI": "http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257"
  },
  "r13": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(19)(a))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r130": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "260",
   "URI": "http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257"
  },
  "r131": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "52",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "10",
   "Topic": "260",
   "URI": "http://asc.fasb.org/extlink&oid=117327953&loc=d3e4984-109258"
  },
  "r132": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "6",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(a)",
   "Topic": "270",
   "URI": "http://asc.fasb.org/extlink&oid=116846552&loc=d3e543-108305"
  },
  "r133": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "270",
   "URI": "http://asc.fasb.org/extlink&oid=118952077&loc=d3e1280-108306"
  },
  "r134": {
   "Name": "Accounting Standards Codification",
   "Publisher": "FASB",
   "Topic": "270",
   "URI": "http://asc.fasb.org/topic&trid=2126967"
  },
  "r135": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "275",
   "URI": "http://asc.fasb.org/extlink&oid=99393423&loc=d3e5967-108592"
  },
  "r136": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(c)",
   "Topic": "275",
   "URI": "http://asc.fasb.org/extlink&oid=99393423&loc=d3e5967-108592"
  },
  "r137": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(d)",
   "Topic": "275",
   "URI": "http://asc.fasb.org/extlink&oid=99393423&loc=d3e5967-108592"
  },
  "r138": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "11",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "275",
   "URI": "http://asc.fasb.org/extlink&oid=99393423&loc=d3e6161-108592"
  },
  "r139": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "12",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "275",
   "URI": "http://asc.fasb.org/extlink&oid=99393423&loc=d3e6191-108592"
  },
  "r14": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(19))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r140": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "275",
   "URI": "http://asc.fasb.org/extlink&oid=99393423&loc=d3e6061-108592"
  },
  "r141": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "8",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "275",
   "URI": "http://asc.fasb.org/extlink&oid=99393423&loc=d3e6132-108592"
  },
  "r142": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "9",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "275",
   "URI": "http://asc.fasb.org/extlink&oid=99393423&loc=d3e6143-108592"
  },
  "r143": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "13",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "280",
   "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8615-108599"
  },
  "r144": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "14",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "280",
   "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8654-108599"
  },
  "r145": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "15",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "280",
   "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8657-108599"
  },
  "r146": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "16",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "280",
   "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8660-108599"
  },
  "r147": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "17",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "280",
   "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8663-108599"
  },
  "r148": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "18",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "280",
   "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8672-108599"
  },
  "r149": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "21",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "280",
   "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8721-108599"
  },
  "r15": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(20))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r150": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "22",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "280",
   "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599"
  },
  "r151": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "22",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(e)",
   "Topic": "280",
   "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599"
  },
  "r152": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "22",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(h)",
   "Topic": "280",
   "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599"
  },
  "r153": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "22",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "280",
   "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599"
  },
  "r154": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "25",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "280",
   "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8813-108599"
  },
  "r155": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "30",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "280",
   "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8906-108599"
  },
  "r156": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "31",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "280",
   "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8924-108599"
  },
  "r157": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "32",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "280",
   "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8933-108599"
  },
  "r158": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "32",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(c)",
   "Topic": "280",
   "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e8933-108599"
  },
  "r159": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "40",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "280",
   "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e9031-108599"
  },
  "r16": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(22))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r160": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "41",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "280",
   "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e9038-108599"
  },
  "r161": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "41",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "280",
   "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e9038-108599"
  },
  "r162": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "42",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "280",
   "URI": "http://asc.fasb.org/extlink&oid=115929826&loc=d3e9054-108599"
  },
  "r163": {
   "Name": "Accounting Standards Codification",
   "Publisher": "FASB",
   "Topic": "280",
   "URI": "http://asc.fasb.org/topic&trid=2134510"
  },
  "r164": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "310",
   "URI": "http://asc.fasb.org/extlink&oid=118952595&loc=d3e4428-111522"
  },
  "r165": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "9",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "310",
   "URI": "http://asc.fasb.org/extlink&oid=118952595&loc=d3e4531-111522"
  },
  "r166": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "310",
   "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=d3e5033-111524"
  },
  "r167": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "310",
   "URI": "http://asc.fasb.org/extlink&oid=118936363&loc=d3e5074-111524"
  },
  "r168": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SAB Topic 4.E)",
   "Topic": "310",
   "URI": "http://asc.fasb.org/extlink&oid=27010918&loc=d3e74512-122707"
  },
  "r169": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Topic": "310",
   "URI": "http://asc.fasb.org/extlink&oid=84159169&loc=d3e10133-111534"
  },
  "r17": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(24))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r170": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Topic": "310",
   "URI": "http://asc.fasb.org/extlink&oid=84159169&loc=d3e10149-111534"
  },
  "r171": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Topic": "310",
   "URI": "http://asc.fasb.org/extlink&oid=84159169&loc=d3e10178-111534"
  },
  "r172": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "20",
   "Topic": "326",
   "URI": "http://asc.fasb.org/extlink&oid=118955202&loc=SL82895884-210446"
  },
  "r173": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "13",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(b)",
   "Topic": "326",
   "URI": "http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447"
  },
  "r174": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "8",
   "Publisher": "FASB",
   "Section": "30",
   "SubTopic": "10",
   "Topic": "330",
   "URI": "http://asc.fasb.org/extlink&oid=68048583&loc=d3e3636-108311"
  },
  "r175": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "35",
   "SubTopic": "10",
   "Topic": "330",
   "URI": "http://asc.fasb.org/extlink&oid=116846819&loc=d3e3927-108312"
  },
  "r176": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "330",
   "URI": "http://asc.fasb.org/extlink&oid=116847112&loc=d3e4492-108314"
  },
  "r177": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "330",
   "URI": "http://asc.fasb.org/extlink&oid=116847112&loc=d3e4556-108314"
  },
  "r178": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "05",
   "SubTopic": "10",
   "Topic": "340",
   "URI": "http://asc.fasb.org/extlink&oid=68074540&loc=d3e5865-108316"
  },
  "r179": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "5",
   "Publisher": "FASB",
   "Section": "05",
   "SubTopic": "10",
   "Topic": "340",
   "URI": "http://asc.fasb.org/extlink&oid=68074540&loc=d3e5879-108316"
  },
  "r18": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(26)(a))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r180": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "20",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266"
  },
  "r181": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "20",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=99380562&loc=d3e13777-109266"
  },
  "r182": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "5",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "20",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975"
  },
  "r183": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(a)",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267"
  },
  "r184": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(e)",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267"
  },
  "r185": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(f)",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267"
  },
  "r186": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(h)",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267"
  },
  "r187": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267"
  },
  "r188": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(b)",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=108376223&loc=d3e13854-109267"
  },
  "r189": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=108376223&loc=d3e13854-109267"
  },
  "r19": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(26)(b))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r190": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "30",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=6388964&loc=d3e16212-109274"
  },
  "r191": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "30",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274"
  },
  "r192": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "30",
   "Subparagraph": "(a)",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275"
  },
  "r193": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "30",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275"
  },
  "r194": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "30",
   "Subparagraph": "((a)(1),(b))",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275"
  },
  "r195": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "30",
   "Subparagraph": "(a)",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275"
  },
  "r196": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "30",
   "Subparagraph": "(a)(1)",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275"
  },
  "r197": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "30",
   "Subparagraph": "(a)(2)",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275"
  },
  "r198": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "30",
   "Subparagraph": "(a)(3)",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275"
  },
  "r199": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "30",
   "Subparagraph": "(b)",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275"
  },
  "r2": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=118951113&loc=d3e6676-107765"
  },
  "r20": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(28))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r200": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "30",
   "Subparagraph": "(b)",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=66006027&loc=d3e16373-109275"
  },
  "r201": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "30",
   "SubTopic": "40",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=118172244&loc=d3e17916-109280"
  },
  "r202": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "6",
   "Publisher": "FASB",
   "Section": "25",
   "SubTopic": "50",
   "Topic": "350",
   "URI": "http://asc.fasb.org/extlink&oid=16397303&loc=d3e19379-109286"
  },
  "r203": {
   "Name": "Accounting Standards Codification",
   "Publisher": "FASB",
   "Topic": "350",
   "URI": "http://asc.fasb.org/topic&trid=2144416"
  },
  "r204": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "05",
   "SubTopic": "10",
   "Topic": "360",
   "URI": "http://asc.fasb.org/extlink&oid=109226317&loc=d3e202-110218"
  },
  "r205": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "5",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "360",
   "URI": "http://asc.fasb.org/extlink&oid=109226348&loc=d3e2443-110228"
  },
  "r206": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a)",
   "Topic": "360",
   "URI": "http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229"
  },
  "r207": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "360",
   "URI": "http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229"
  },
  "r208": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(c)",
   "Topic": "360",
   "URI": "http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229"
  },
  "r209": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "360",
   "URI": "http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229"
  },
  "r21": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(29))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r210": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(c)",
   "Topic": "360",
   "URI": "http://asc.fasb.org/extlink&oid=109226691&loc=d3e2941-110230"
  },
  "r211": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(d)",
   "Topic": "360",
   "URI": "http://asc.fasb.org/extlink&oid=109226691&loc=d3e2941-110230"
  },
  "r212": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(f)",
   "Topic": "360",
   "URI": "http://asc.fasb.org/extlink&oid=109226691&loc=d3e2941-110230"
  },
  "r213": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SAB Topic 5.CC)",
   "Topic": "360",
   "URI": "http://asc.fasb.org/extlink&oid=27011434&loc=d3e125687-122742"
  },
  "r214": {
   "Name": "Accounting Standards Codification",
   "Publisher": "FASB",
   "Topic": "360",
   "URI": "http://asc.fasb.org/topic&trid=2155823"
  },
  "r215": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(b)(2)",
   "Topic": "420",
   "URI": "http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869"
  },
  "r216": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(d)",
   "Topic": "420",
   "URI": "http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869"
  },
  "r217": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "420",
   "URI": "http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869"
  },
  "r218": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SAB TOPIC 5.P.3)",
   "Topic": "420",
   "URI": "http://asc.fasb.org/extlink&oid=115931487&loc=d3e140864-122747"
  },
  "r219": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SAB TOPIC 5.P.4(b))",
   "Topic": "420",
   "URI": "http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747"
  },
  "r22": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(3))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r220": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SAB TOPIC 5.P.4)",
   "Topic": "420",
   "URI": "http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747"
  },
  "r221": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SAB Topic 5.P.4(d))",
   "Topic": "420",
   "URI": "http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747"
  },
  "r222": {
   "Name": "Accounting Standards Codification",
   "Publisher": "FASB",
   "Topic": "420",
   "URI": "http://asc.fasb.org/topic&trid=2175745"
  },
  "r223": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "10",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Topic": "450",
   "URI": "http://asc.fasb.org/extlink&oid=118942415&loc=d3e14615-108349"
  },
  "r224": {
   "Name": "Accounting Standards Codification",
   "Publisher": "FASB",
   "Topic": "450",
   "URI": "http://asc.fasb.org/topic&trid=2127136"
  },
  "r225": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "8",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "460",
   "URI": "http://asc.fasb.org/extlink&oid=68068213&loc=d3e12565-110249"
  },
  "r226": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "12A",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "470",
   "URI": "http://asc.fasb.org/extlink&oid=99376301&loc=SL5988623-112600"
  },
  "r227": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "470",
   "URI": "http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601"
  },
  "r228": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "5",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "470",
   "URI": "http://asc.fasb.org/extlink&oid=6802200&loc=SL6230698-112601"
  },
  "r229": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(b)(1)",
   "Topic": "470",
   "URI": "http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870"
  },
  "r23": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(30)(a)(1))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r230": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(b)(2)",
   "Topic": "470",
   "URI": "http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870"
  },
  "r231": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "6",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(a)",
   "Topic": "470",
   "URI": "http://asc.fasb.org/extlink&oid=109500613&loc=SL6036836-161870"
  },
  "r232": {
   "Name": "Accounting Standards Codification",
   "Publisher": "FASB",
   "Topic": "470",
   "URI": "http://asc.fasb.org/topic&trid=2208564"
  },
  "r233": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "505",
   "URI": "http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644"
  },
  "r234": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "505",
   "URI": "http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644"
  },
  "r235": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "6",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "505",
   "URI": "http://asc.fasb.org/extlink&oid=109259400&loc=d3e21506-112644"
  },
  "r236": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "7",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "505",
   "URI": "http://asc.fasb.org/extlink&oid=109259400&loc=d3e21521-112644"
  },
  "r237": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "8",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "505",
   "URI": "http://asc.fasb.org/extlink&oid=109259400&loc=d3e21538-112644"
  },
  "r238": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.3-04)",
   "Topic": "505",
   "URI": "http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770"
  },
  "r239": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Topic": "505",
   "URI": "http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770"
  },
  "r24": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(30)(a)(3))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r240": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "30",
   "Topic": "505",
   "URI": "http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655"
  },
  "r241": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "30",
   "Topic": "505",
   "URI": "http://asc.fasb.org/extlink&oid=6405834&loc=d3e23315-112656"
  },
  "r242": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a)",
   "Topic": "606",
   "URI": "http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045"
  },
  "r243": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "5",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "606",
   "URI": "http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045"
  },
  "r244": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "8",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a)",
   "Topic": "606",
   "URI": "http://asc.fasb.org/extlink&oid=118956577&loc=SL49130549-203045"
  },
  "r245": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "27",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "10",
   "Topic": "606",
   "URI": "http://asc.fasb.org/extlink&oid=118944142&loc=SL49130611-203046-203046"
  },
  "r246": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "91",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "10",
   "Subparagraph": "(a)",
   "Topic": "606",
   "URI": "http://asc.fasb.org/extlink&oid=118944142&loc=SL49130690-203046-203046"
  },
  "r247": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "91",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "606",
   "URI": "http://asc.fasb.org/extlink&oid=118944142&loc=SL49130690-203046-203046"
  },
  "r248": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "91",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "10",
   "Subparagraph": "(c)",
   "Topic": "606",
   "URI": "http://asc.fasb.org/extlink&oid=118944142&loc=SL49130690-203046-203046"
  },
  "r249": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "91",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "10",
   "Subparagraph": "(d)",
   "Topic": "606",
   "URI": "http://asc.fasb.org/extlink&oid=118944142&loc=SL49130690-203046-203046"
  },
  "r25": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(30))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r250": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "91",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "10",
   "Subparagraph": "(e)",
   "Topic": "606",
   "URI": "http://asc.fasb.org/extlink&oid=118944142&loc=SL49130690-203046-203046"
  },
  "r251": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "91",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "10",
   "Subparagraph": "(f)",
   "Topic": "606",
   "URI": "http://asc.fasb.org/extlink&oid=118944142&loc=SL49130690-203046-203046"
  },
  "r252": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "91",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "10",
   "Subparagraph": "(g)",
   "Topic": "606",
   "URI": "http://asc.fasb.org/extlink&oid=118944142&loc=SL49130690-203046-203046"
  },
  "r253": {
   "Name": "Accounting Standards Codification",
   "Publisher": "FASB",
   "Topic": "606",
   "URI": "http://asc.fasb.org/topic&trid=49130388"
  },
  "r254": {
   "Name": "Accounting Standards Codification",
   "Publisher": "FASB",
   "Topic": "705",
   "URI": "http://asc.fasb.org/topic&trid=2122478"
  },
  "r255": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "15",
   "SubTopic": "10",
   "Subparagraph": "(c)",
   "Topic": "712",
   "URI": "http://asc.fasb.org/extlink&oid=6410066&loc=d3e79218-111664"
  },
  "r256": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "15",
   "SubTopic": "10",
   "Subparagraph": "(d)",
   "Topic": "712",
   "URI": "http://asc.fasb.org/extlink&oid=6410066&loc=d3e79218-111664"
  },
  "r257": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "20",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=109237824&loc=d3e1703-114919"
  },
  "r258": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "20",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=109237824&loc=d3e1731-114919"
  },
  "r259": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(a)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r26": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(31))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r260": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(a)(1)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r261": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(a)(2)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r262": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(a)(3)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r263": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(a)(4)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r264": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(a)(6)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r265": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(a)(7)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r266": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(b)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r267": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(b)(1)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r268": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(b)(4)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r269": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(b)(5)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r27": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(32))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r270": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(c)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r271": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(d)(5)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r272": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(d)(ii)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r273": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(d)(iv)(01)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r274": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(f)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r275": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(h)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r276": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(h)(1)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r277": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(h)(2)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r278": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(h)(3)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r279": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(h)(4)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r28": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(4)",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r280": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(h)(5)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r281": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(i)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r282": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(j)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r283": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(k)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r284": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(k)(1)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r285": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(k)(3)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r286": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(l)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r287": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(n)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r288": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920"
  },
  "r289": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e2410-114920"
  },
  "r29": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(7))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r290": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e2417-114920"
  },
  "r291": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e2439-114920"
  },
  "r292": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "6",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(a)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e2709-114920"
  },
  "r293": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "6",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(a)(1)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e2709-114920"
  },
  "r294": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "6",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(a)(2)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e2709-114920"
  },
  "r295": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "6",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(a)(3)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e2709-114920"
  },
  "r296": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "6",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(a)(4)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e2709-114920"
  },
  "r297": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "6",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(a)(5)",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118255775&loc=d3e2709-114920"
  },
  "r298": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "17",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "20",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=118257860&loc=d3e4179-114921"
  },
  "r299": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "60",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=6414203&loc=d3e39716-114964"
  },
  "r3": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(c)",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=118951113&loc=d3e6676-107765"
  },
  "r30": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(8))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r300": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "70",
   "Topic": "715",
   "URI": "http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942"
  },
  "r301": {
   "Name": "Accounting Standards Codification",
   "Publisher": "FASB",
   "Topic": "715",
   "URI": "http://asc.fasb.org/topic&trid=2235017"
  },
  "r302": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a)",
   "Topic": "718",
   "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5047-113901"
  },
  "r303": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "718",
   "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5047-113901"
  },
  "r304": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "718",
   "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5047-113901"
  },
  "r305": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a)(1)",
   "Topic": "718",
   "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901"
  },
  "r306": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a)(2)",
   "Topic": "718",
   "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901"
  },
  "r307": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a),(g)",
   "Topic": "718",
   "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901"
  },
  "r308": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(b),(f)",
   "Topic": "718",
   "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901"
  },
  "r309": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(c)(1)(iv)(2)",
   "Topic": "718",
   "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901"
  },
  "r31": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02.1)",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r310": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(c)(1)(iv)(3)",
   "Topic": "718",
   "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901"
  },
  "r311": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(c)(2)(i)-(ii)",
   "Topic": "718",
   "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901"
  },
  "r312": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(c)(2)(iii)(1)",
   "Topic": "718",
   "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901"
  },
  "r313": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(c)(2)(iii)(2)",
   "Topic": "718",
   "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901"
  },
  "r314": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(c)(2)(iii)(3)",
   "Topic": "718",
   "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901"
  },
  "r315": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(f)",
   "Topic": "718",
   "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901"
  },
  "r316": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(g)",
   "Topic": "718",
   "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901"
  },
  "r317": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(h)(1)(i)",
   "Topic": "718",
   "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901"
  },
  "r318": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(i)",
   "Topic": "718",
   "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901"
  },
  "r319": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "718",
   "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901"
  },
  "r32": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02.13(a))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r320": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2A",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a)",
   "Topic": "718",
   "URI": "http://asc.fasb.org/extlink&oid=116856206&loc=SL79508275-113901"
  },
  "r321": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SAB Topic 14.F)",
   "Topic": "718",
   "URI": "http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809"
  },
  "r322": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "24",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "20",
   "Topic": "718",
   "URI": "http://asc.fasb.org/extlink&oid=118258462&loc=d3e11374-113907"
  },
  "r323": {
   "Name": "Accounting Standards Codification",
   "Publisher": "FASB",
   "Topic": "718",
   "URI": "http://asc.fasb.org/topic&trid=2228938"
  },
  "r324": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "35",
   "Subparagraph": "(a)",
   "Topic": "720",
   "URI": "http://asc.fasb.org/extlink&oid=6420018&loc=d3e36677-107848"
  },
  "r325": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "35",
   "Subparagraph": "(b)",
   "Topic": "720",
   "URI": "http://asc.fasb.org/extlink&oid=6420018&loc=d3e36677-107848"
  },
  "r326": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "20",
   "Publisher": "FASB",
   "Section": "25",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=117330534&loc=d3e28680-109314"
  },
  "r327": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "20",
   "Publisher": "FASB",
   "Section": "25",
   "SubTopic": "10",
   "Subparagraph": "(d)",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=117330534&loc=d3e28680-109314"
  },
  "r328": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "20",
   "Publisher": "FASB",
   "Section": "25",
   "SubTopic": "10",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=117330534&loc=d3e28680-109314"
  },
  "r329": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "25",
   "SubTopic": "10",
   "Subparagraph": "(a)(1)",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=117330534&loc=d3e28200-109314"
  },
  "r33": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02.13)",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r330": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "10B",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=116821951&loc=SL37586934-109318"
  },
  "r331": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "20",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=116821951&loc=d3e32123-109318"
  },
  "r332": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "25",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=116821951&loc=d3e32247-109318"
  },
  "r333": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "28",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=116821951&loc=d3e32280-109318"
  },
  "r334": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "6",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=116821951&loc=d3e31931-109318"
  },
  "r335": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "10",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32672-109319"
  },
  "r336": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "12",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319"
  },
  "r337": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "13",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319"
  },
  "r338": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "15",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(d)",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32718-109319"
  },
  "r339": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "15A",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a)",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319"
  },
  "r34": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02.14)",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r340": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "15A",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a)(1)",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319"
  },
  "r341": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "15A",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a)(2)",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319"
  },
  "r342": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "15A",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a)(3)",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319"
  },
  "r343": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "15A",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a)(4)",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319"
  },
  "r344": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "15A",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319"
  },
  "r345": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "17",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32809-109319"
  },
  "r346": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "19",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32840-109319"
  },
  "r347": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a)",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319"
  },
  "r348": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319"
  },
  "r349": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(b),(c)",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319"
  },
  "r35": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02.17)",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r350": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(c)",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319"
  },
  "r351": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319"
  },
  "r352": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "20",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32847-109319"
  },
  "r353": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a)",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32559-109319"
  },
  "r354": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "6",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32621-109319"
  },
  "r355": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "8",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32632-109319"
  },
  "r356": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "9",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a)",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32639-109319"
  },
  "r357": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "9",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a)-(b)",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32639-109319"
  },
  "r358": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "9",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32639-109319"
  },
  "r359": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "9",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=84230637&loc=d3e32639-109319"
  },
  "r36": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02.19(a))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r360": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SAB Topic 6.I.7)",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=116825942&loc=d3e330036-122817"
  },
  "r361": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "20",
   "Subparagraph": "(a)",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=109238882&loc=d3e38679-109324"
  },
  "r362": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "05",
   "SubTopic": "30",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=65884525&loc=d3e40913-109327"
  },
  "r363": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "30",
   "Subparagraph": "(b)(c)",
   "Topic": "740",
   "URI": "http://asc.fasb.org/extlink&oid=6424122&loc=d3e41874-109331"
  },
  "r364": {
   "Name": "Accounting Standards Codification",
   "Publisher": "FASB",
   "Topic": "740",
   "URI": "http://asc.fasb.org/topic&trid=2144680"
  },
  "r365": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "805",
   "URI": "http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463"
  },
  "r366": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "805",
   "URI": "http://asc.fasb.org/extlink&oid=79982066&loc=d3e1486-128463"
  },
  "r367": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "13",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "20",
   "Topic": "805",
   "URI": "http://asc.fasb.org/extlink&oid=77890550&loc=d3e5227-128473"
  },
  "r368": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "14",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "20",
   "Subparagraph": "(a)",
   "Topic": "805",
   "URI": "http://asc.fasb.org/extlink&oid=77890550&loc=d3e5263-128473"
  },
  "r369": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "15",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "810",
   "URI": "http://asc.fasb.org/extlink&oid=108774443&loc=SL4568447-111683"
  },
  "r37": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02.19(b))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r370": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "16",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "810",
   "URI": "http://asc.fasb.org/extlink&oid=108774443&loc=SL4568740-111683"
  },
  "r371": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "19",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "810",
   "URI": "http://asc.fasb.org/extlink&oid=108774443&loc=SL4569616-111683"
  },
  "r372": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "20",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "810",
   "URI": "http://asc.fasb.org/extlink&oid=108774443&loc=SL4569643-111683"
  },
  "r373": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "21",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "810",
   "URI": "http://asc.fasb.org/extlink&oid=108774443&loc=SL4613674-111683"
  },
  "r374": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "23",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "810",
   "URI": "http://asc.fasb.org/extlink&oid=108774443&loc=SL4569655-111683"
  },
  "r375": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "810",
   "URI": "http://asc.fasb.org/extlink&oid=109239629&loc=d3e5614-111684"
  },
  "r376": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1A",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a)(1)",
   "Topic": "810",
   "URI": "http://asc.fasb.org/extlink&oid=109239629&loc=SL4573702-111684"
  },
  "r377": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1A",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a)(2)",
   "Topic": "810",
   "URI": "http://asc.fasb.org/extlink&oid=109239629&loc=SL4573702-111684"
  },
  "r378": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1A",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(c)(1)",
   "Topic": "810",
   "URI": "http://asc.fasb.org/extlink&oid=109239629&loc=SL4573702-111684"
  },
  "r379": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1A",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(c)(2)",
   "Topic": "810",
   "URI": "http://asc.fasb.org/extlink&oid=109239629&loc=SL4573702-111684"
  },
  "r38": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02.19(b),22(b))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r380": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1A",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(c)(3)",
   "Topic": "810",
   "URI": "http://asc.fasb.org/extlink&oid=109239629&loc=SL4573702-111684"
  },
  "r381": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1A",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(c),(3)",
   "Topic": "810",
   "URI": "http://asc.fasb.org/extlink&oid=109239629&loc=SL4573702-111684"
  },
  "r382": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4I",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "10",
   "Topic": "810",
   "URI": "http://asc.fasb.org/extlink&oid=116874947&loc=SL4590271-111686"
  },
  "r383": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4J",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "10",
   "Topic": "810",
   "URI": "http://asc.fasb.org/extlink&oid=116874947&loc=SL4591551-111686"
  },
  "r384": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4K",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "10",
   "Topic": "810",
   "URI": "http://asc.fasb.org/extlink&oid=116874947&loc=SL4591552-111686"
  },
  "r385": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.3A-02)",
   "Topic": "810",
   "URI": "http://asc.fasb.org/extlink&oid=116822174&loc=d3e355033-122828"
  },
  "r386": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.3A-03)",
   "Topic": "810",
   "URI": "http://asc.fasb.org/extlink&oid=116822174&loc=d3e355100-122828"
  },
  "r387": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4A",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a)",
   "Topic": "815",
   "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959"
  },
  "r388": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4B",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(d)",
   "Topic": "815",
   "URI": "http://asc.fasb.org/extlink&oid=109980867&loc=SL5624163-113959"
  },
  "r389": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(a)",
   "Topic": "820",
   "URI": "http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258"
  },
  "r39": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02.19)",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r390": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "820",
   "URI": "http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258"
  },
  "r391": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Subparagraph": "(c)",
   "Topic": "820",
   "URI": "http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258"
  },
  "r392": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "820",
   "URI": "http://asc.fasb.org/extlink&oid=117815213&loc=d3e19279-110258"
  },
  "r393": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Topic": "830",
   "URI": "http://asc.fasb.org/extlink&oid=6450222&loc=d3e30840-110895"
  },
  "r394": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "230",
   "Topic": "830",
   "URI": "http://asc.fasb.org/extlink&oid=98513438&loc=d3e33268-110906"
  },
  "r395": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "12",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "30",
   "Topic": "830",
   "URI": "http://asc.fasb.org/extlink&oid=118261656&loc=d3e32022-110900"
  },
  "r396": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "18",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "30",
   "Topic": "830",
   "URI": "http://asc.fasb.org/extlink&oid=118261656&loc=d3e32157-110900"
  },
  "r397": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "20",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "30",
   "Topic": "830",
   "URI": "http://asc.fasb.org/extlink&oid=118261656&loc=d3e32211-110900"
  },
  "r398": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "30",
   "Topic": "830",
   "URI": "http://asc.fasb.org/extlink&oid=6450520&loc=d3e32583-110901"
  },
  "r399": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(b)",
   "Topic": "835",
   "URI": "http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391"
  },
  "r4": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(g)(4)",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=118951113&loc=d3e6676-107765"
  },
  "r40": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02.19,20)",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r400": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1A",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "30",
   "Topic": "835",
   "URI": "http://asc.fasb.org/extlink&oid=114775744&loc=d3e28541-108399"
  },
  "r401": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "30",
   "Topic": "835",
   "URI": "http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399"
  },
  "r402": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "30",
   "Topic": "835",
   "URI": "http://asc.fasb.org/extlink&oid=114775744&loc=d3e28555-108399"
  },
  "r403": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "8",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "30",
   "Topic": "835",
   "URI": "http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400"
  },
  "r404": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "40",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "10",
   "Subparagraph": "(Note 3)",
   "Topic": "840",
   "URI": "http://asc.fasb.org/extlink&oid=82846649&loc=d3e38371-112697"
  },
  "r405": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "20",
   "Subparagraph": "(a)",
   "Topic": "842",
   "URI": "http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977"
  },
  "r406": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "20",
   "Subparagraph": "(b)",
   "Topic": "842",
   "URI": "http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977"
  },
  "r407": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "5",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "20",
   "Subparagraph": "(c)",
   "Topic": "842",
   "URI": "http://asc.fasb.org/extlink&oid=77888419&loc=SL77918643-209977"
  },
  "r408": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(b)",
   "Topic": "842",
   "URI": "http://asc.fasb.org/extlink&oid=77888426&loc=SL77918666-209980"
  },
  "r409": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(a)(3)",
   "Topic": "842",
   "URI": "http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980"
  },
  "r41": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02.20)",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r410": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Topic": "842",
   "URI": "http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980"
  },
  "r411": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(b)",
   "Topic": "842",
   "URI": "http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980"
  },
  "r412": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(g)(1)",
   "Topic": "842",
   "URI": "http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980"
  },
  "r413": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(g)(2)",
   "Topic": "842",
   "URI": "http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980"
  },
  "r414": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(g)(3)",
   "Topic": "842",
   "URI": "http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980"
  },
  "r415": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(g)(4)",
   "Topic": "842",
   "URI": "http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980"
  },
  "r416": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Topic": "842",
   "URI": "http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980"
  },
  "r417": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "6",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Topic": "842",
   "URI": "http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980"
  },
  "r418": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "53",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "20",
   "Topic": "842",
   "URI": "http://asc.fasb.org/extlink&oid=77888399&loc=SL77918982-209971"
  },
  "r419": {
   "Name": "Accounting Standards Codification",
   "Publisher": "FASB",
   "SubTopic": "20",
   "Topic": "842",
   "URI": "http://asc.fasb.org/subtopic&trid=77888251"
  },
  "r42": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02.21)",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r420": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "855",
   "URI": "http://asc.fasb.org/extlink&oid=6842918&loc=SL6314017-165662"
  },
  "r421": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "855",
   "URI": "http://asc.fasb.org/extlink&oid=6842918&loc=SL6314020-165662"
  },
  "r422": {
   "Name": "Accounting Standards Codification",
   "Publisher": "FASB",
   "Topic": "855",
   "URI": "http://asc.fasb.org/topic&trid=2122774"
  },
  "r423": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(bb)",
   "Topic": "860",
   "URI": "http://asc.fasb.org/extlink&oid=118948506&loc=d3e107207-111719"
  },
  "r424": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "20",
   "Subparagraph": "(bb)(1)",
   "Topic": "860",
   "URI": "http://asc.fasb.org/extlink&oid=118948506&loc=d3e107207-111719"
  },
  "r425": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "340",
   "Topic": "928",
   "URI": "http://asc.fasb.org/extlink&oid=6473545&loc=d3e61844-108004"
  },
  "r426": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "25",
   "SubTopic": "20",
   "Topic": "940",
   "URI": "http://asc.fasb.org/extlink&oid=68072869&loc=d3e41242-110953"
  },
  "r427": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.9-03(11))",
   "Topic": "942",
   "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878"
  },
  "r428": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.9-03(13)(2))",
   "Topic": "942",
   "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878"
  },
  "r429": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.9-03(13))",
   "Topic": "942",
   "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878"
  },
  "r43": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02.22(a)(1))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r430": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.9-03(15)(1))",
   "Topic": "942",
   "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878"
  },
  "r431": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.9-03(15)(2))",
   "Topic": "942",
   "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878"
  },
  "r432": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.9-03(15))",
   "Topic": "942",
   "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878"
  },
  "r433": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.9-03(16))",
   "Topic": "942",
   "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878"
  },
  "r434": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.9-03(22))",
   "Topic": "942",
   "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878"
  },
  "r435": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.9-03(23))",
   "Topic": "942",
   "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878"
  },
  "r436": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.9-03.15(5))",
   "Topic": "942",
   "URI": "http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878"
  },
  "r437": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "220",
   "Subparagraph": "(SX 210.9-04(15))",
   "Topic": "942",
   "URI": "http://asc.fasb.org/extlink&oid=116637391&loc=SL114874048-224260"
  },
  "r438": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "220",
   "Subparagraph": "(SX 210.9-04(22))",
   "Topic": "942",
   "URI": "http://asc.fasb.org/extlink&oid=116637391&loc=SL114874048-224260"
  },
  "r439": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "220",
   "Subparagraph": "(SX 210.9-04(23))",
   "Topic": "942",
   "URI": "http://asc.fasb.org/extlink&oid=116637391&loc=SL114874048-224260"
  },
  "r44": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02.22)",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r440": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "220",
   "Subparagraph": "(SX 210.9-04.10)",
   "Topic": "942",
   "URI": "http://asc.fasb.org/extlink&oid=116637391&loc=SL114874048-224260"
  },
  "r441": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "470",
   "Subparagraph": "e",
   "Topic": "942",
   "URI": "http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823"
  },
  "r442": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "470",
   "Topic": "942",
   "URI": "http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823"
  },
  "r443": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "740",
   "Subparagraph": "(b)",
   "Topic": "942",
   "URI": "http://asc.fasb.org/extlink&oid=6479915&loc=d3e66715-112838"
  },
  "r444": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "825",
   "Topic": "942",
   "URI": "http://asc.fasb.org/extlink&oid=108315417&loc=d3e61044-112788"
  },
  "r445": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.7-03(15)(b)(2))",
   "Topic": "944",
   "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910"
  },
  "r446": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.7-03(16))",
   "Topic": "944",
   "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910"
  },
  "r447": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.7-03(a)(12))",
   "Topic": "944",
   "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910"
  },
  "r448": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.7-03(a)(15)(b)(1))",
   "Topic": "944",
   "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910"
  },
  "r449": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.7-03(a)(15))",
   "Topic": "944",
   "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910"
  },
  "r45": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02.29,30)",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r450": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.7-03(a)(16)(a)(1))",
   "Topic": "944",
   "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910"
  },
  "r451": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.7-03(a)(16))",
   "Topic": "944",
   "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910"
  },
  "r452": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.7-03(a)(23)(a)(4))",
   "Topic": "944",
   "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910"
  },
  "r453": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.7-03(a)(24))",
   "Topic": "944",
   "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910"
  },
  "r454": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.7-03(a)(25))",
   "Topic": "944",
   "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910"
  },
  "r455": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.7-03(a)(8))",
   "Topic": "944",
   "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910"
  },
  "r456": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.7-03.15(a))",
   "Topic": "944",
   "URI": "http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910"
  },
  "r457": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "220",
   "Subparagraph": "(SX 210.7-04(18))",
   "Topic": "944",
   "URI": "http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263"
  },
  "r458": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "220",
   "Subparagraph": "(SX 210.7-04(19))",
   "Topic": "944",
   "URI": "http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263"
  },
  "r459": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "220",
   "Subparagraph": "(SX 210.7-04(8))",
   "Topic": "944",
   "URI": "http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263"
  },
  "r46": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02.29-31)",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r460": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "4H",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "40",
   "Topic": "944",
   "URI": "http://asc.fasb.org/extlink&oid=116884468&loc=SL65671331-158438"
  },
  "r461": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "13H",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "40",
   "Subparagraph": "(a)",
   "Topic": "944",
   "URI": "http://asc.fasb.org/extlink&oid=117419784&loc=SL117783719-158441"
  },
  "r462": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "13H",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "40",
   "Subparagraph": "(b)",
   "Topic": "944",
   "URI": "http://asc.fasb.org/extlink&oid=117419784&loc=SL117783719-158441"
  },
  "r463": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "13H",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "40",
   "Subparagraph": "(c)",
   "Topic": "944",
   "URI": "http://asc.fasb.org/extlink&oid=117419784&loc=SL117783719-158441"
  },
  "r464": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "740",
   "Subparagraph": "(b)",
   "Topic": "944",
   "URI": "http://asc.fasb.org/extlink&oid=6487024&loc=d3e29054-158556"
  },
  "r465": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "210",
   "Subparagraph": "(SX 210.6-04.16)",
   "Topic": "946",
   "URI": "http://asc.fasb.org/extlink&oid=6488278&loc=d3e603758-122996"
  },
  "r466": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "310",
   "Subparagraph": "(SX 210.12-29(Footnote 4))",
   "Topic": "948",
   "URI": "http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014"
  },
  "r467": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "450",
   "Topic": "954",
   "URI": "http://asc.fasb.org/extlink&oid=6491354&loc=d3e6049-115624"
  },
  "r468": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "450",
   "Topic": "954",
   "URI": "http://asc.fasb.org/extlink&oid=6491354&loc=d3e6052-115624"
  },
  "r469": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "740",
   "Topic": "954",
   "URI": "http://asc.fasb.org/extlink&oid=6491622&loc=d3e9504-115650"
  },
  "r47": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02.31)",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r470": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "360",
   "Subparagraph": "(SX 210.12-28(Footnote 2))",
   "Topic": "970",
   "URI": "http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024"
  },
  "r471": {
   "Name": "Exchange Act",
   "Number": "240",
   "Publisher": "SEC",
   "Section": "12",
   "Subsection": "b"
  },
  "r472": {
   "Name": "Exchange Act",
   "Number": "240",
   "Publisher": "SEC",
   "Section": "12",
   "Subsection": "b-23"
  },
  "r473": {
   "Name": "Exchange Act",
   "Number": "240",
   "Publisher": "SEC",
   "Section": "12",
   "Subsection": "d1-1"
  },
  "r474": {
   "Name": "Forms 10-K, 10-Q, 20-F",
   "Number": "240",
   "Publisher": "SEC",
   "Section": "13",
   "Subsection": "a-1-"
  },
  "r475": {
   "Name": "Forms 10-K, 20-F, 40-F",
   "Number": "240",
   "Publisher": "SEC",
   "Section": "15",
   "Subsection": "d-1"
  },
  "r476": {
   "Name": "Regulation 12B",
   "Number": "240",
   "Publisher": "SEC",
   "Section": "12",
   "Subsection": "b-2"
  },
  "r477": {
   "Name": "Regulation S-T",
   "Number": "232",
   "Publisher": "SEC",
   "Section": "405"
  },
  "r48": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02.6(a))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r49": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02.6(b))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r5": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=118951113&loc=d3e6676-107765"
  },
  "r50": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02.6(c))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r51": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02.9)",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r52": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "10A",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(a),(b),(c)",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580"
  },
  "r53": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "10A",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(a-c)",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580"
  },
  "r54": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "10A",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(i),(j),(k)",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580"
  },
  "r55": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "10A",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(i-k)",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580"
  },
  "r56": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "10A",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580"
  },
  "r57": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "11",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=d3e637-108580"
  },
  "r58": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "12",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=d3e640-108580"
  },
  "r59": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "14",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=d3e681-108580"
  },
  "r6": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=118951113&loc=d3e6787-107765"
  },
  "r60": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "14A",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669686-108580"
  },
  "r61": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "15",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=d3e689-108580"
  },
  "r62": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "17A",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL34724391-108580"
  },
  "r63": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "17B",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL34724394-108580"
  },
  "r64": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1A",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(a)",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669619-108580"
  },
  "r65": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1A",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669619-108580"
  },
  "r66": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1A",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(c)",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669619-108580"
  },
  "r67": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1B",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(a)",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669625-108580"
  },
  "r68": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1B",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=SL7669625-108580"
  },
  "r69": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "5",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=118930883&loc=d3e557-108580"
  },
  "r7": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "3",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=118951113&loc=d3e6801-107765"
  },
  "r70": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=116657188&loc=SL116659661-227067"
  },
  "r71": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "15",
   "Publisher": "FASB",
   "Section": "55",
   "SubTopic": "10",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=118951672&loc=d3e1436-108581"
  },
  "r72": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-03(10))",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227"
  },
  "r73": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-03(20))",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227"
  },
  "r74": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-03(21))",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227"
  },
  "r75": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-03(5))",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227"
  },
  "r76": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-03.1,2)",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227"
  },
  "r77": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-03.2(a),(d))",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227"
  },
  "r78": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-03.4)",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227"
  },
  "r79": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-03.7)",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227"
  },
  "r8": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "50",
   "SubTopic": "10",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6361739&loc=d3e7789-107766"
  },
  "r80": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-03.9)",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227"
  },
  "r81": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Topic": "220",
   "URI": "http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227"
  },
  "r82": {
   "Name": "Accounting Standards Codification",
   "Publisher": "FASB",
   "Topic": "220",
   "URI": "http://asc.fasb.org/topic&trid=2134417"
  },
  "r83": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "12",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3179-108585"
  },
  "r84": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "12",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(c)",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3179-108585"
  },
  "r85": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "12",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3179-108585"
  },
  "r86": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "13",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3213-108585"
  },
  "r87": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "13",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(c)",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3213-108585"
  },
  "r88": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "13",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3213-108585"
  },
  "r89": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "14",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(a)",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3255-108585"
  },
  "r9": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "1",
   "Publisher": "FASB",
   "Section": "S99",
   "SubTopic": "10",
   "Subparagraph": "(SX 210.5-02(1))",
   "Topic": "210",
   "URI": "http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682"
  },
  "r90": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "14",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3255-108585"
  },
  "r91": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "14",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3255-108585"
  },
  "r92": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "15",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(a)",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585"
  },
  "r93": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "15",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(b)",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585"
  },
  "r94": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "15",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585"
  },
  "r95": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "17",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(d)",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3367-108585"
  },
  "r96": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "2",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3000-108585"
  },
  "r97": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "21D",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=SL94080555-108585"
  },
  "r98": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "24",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3521-108585"
  },
  "r99": {
   "Name": "Accounting Standards Codification",
   "Paragraph": "25",
   "Publisher": "FASB",
   "Section": "45",
   "SubTopic": "10",
   "Subparagraph": "(e)",
   "Topic": "230",
   "URI": "http://asc.fasb.org/extlink&oid=118932676&loc=d3e3536-108585"
  }
 },
 "version": "2.1"
}
