GOODWILL	9 Months Ended
Sep. 30, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL	GOODWILL At September 30, 2016, Grainger had approximately $1 billion of Goodwill and Intangible assets, or 17% of total assets. Grainger annually reviews goodwill and intangible assets with indefinite lives for impairment in the fourth quarter and when events or changes in circumstances indicate the carrying value of these assets might exceed their current fair values. Grainger tests for goodwill impairment at the reporting unit level and performs a qualitative assessment of factors such as a reporting unit's current performance and overall economic factors to determine if it is more likely than not that the goodwill might be impaired and whether it is necessary to perform the two-step quantitative goodwill impairment test. In the two-step test, Grainger first compares the carrying value of assets of the reporting unit to its calculated fair value. If the carrying value of assets of the reporting unit exceeds its calculated fair value, the second step is performed, where the implied fair value of goodwill is compared to the carrying value of that goodwill, to determine the amount of impairment. The fair value of reporting units is calculated primarily using the discounted cash flow (DCF) method and incorporating value indicators from a market approach to evaluate the reasonableness of the resulting fair values. The DCF method incorporates various assumptions including the amount and timing of future expected cash flows, including revenues, gross margins, operating expenses, capital expenditures and working capital based on operational budgets, long range strategic plans and other estimates. The terminal value growth rate is used to calculate the value of cash flows beyond the last projected period and reflects management’s best estimates for perpetual growth for the reporting units. Estimates of market participant risk-adjusted weighted average cost of capital are used as a basis for determining the discount rates to apply to the reporting units’ future expected cash flows and terminal value. As previously reported, Grainger completed the annual impairment testing during the fourth quarter of 2015, including the quantitative test for Fabory, with $106 million of goodwill at December 31, 2015. The fair value of the Fabory reporting unit's goodwill exceeded the carrying value by 15%, and the step two calculation was not required. For the Company's remaining reporting units, the estimated fair values substantially exceeded the carrying values. Grainger monitors the operating performance of Fabory and the quarterly assessment did not indicate the presence of any goodwill impairment triggering events as of September 30, 2016. If Fabory's future earnings and cash flows projections are not achieved or economic conditions in Europe deteriorate, future impairment of Fabory's intangible assets, including goodwill, could result.

GOODWILL

At September 30, 2016, Grainger had approximately $1 billion of Goodwill and Intangible assets, or 17% of total assets. Grainger annually reviews goodwill and intangible assets with indefinite lives for impairment in the fourth quarter and when events or changes in circumstances indicate the carrying value of these assets might exceed their current fair values. Grainger tests for goodwill impairment at the reporting unit level and performs a qualitative assessment of factors such as a reporting unit's current performance and overall economic factors to determine if it is more likely than not that the goodwill might be impaired and whether it is necessary to perform the two-step quantitative goodwill impairment test. In the two-step test, Grainger first compares the carrying value of assets of the reporting unit to its calculated fair value. If the carrying value of assets of the reporting unit exceeds its calculated fair value, the second step is performed, where the implied fair value of goodwill is compared to the carrying value of that goodwill, to determine the amount of impairment.

The fair value of reporting units is calculated primarily using the discounted cash flow (DCF) method and incorporating value indicators from a market approach to evaluate the reasonableness of the resulting fair values. The DCF method incorporates various assumptions including the amount and timing of future expected cash flows, including revenues, gross margins, operating expenses, capital expenditures and working capital based on operational budgets, long range strategic plans and other estimates. The terminal value growth rate is used to calculate the value of cash flows beyond the last projected period and reflects management’s best estimates for perpetual growth for the reporting units. Estimates of market participant risk-adjusted weighted average cost of capital are used as a basis for determining the discount rates to apply to the reporting units’ future expected cash flows and terminal value.

As previously reported, Grainger completed the annual impairment testing during the fourth quarter of 2015, including the quantitative test for Fabory, with $106 million of goodwill at December 31, 2015. The fair value of the Fabory reporting unit's goodwill exceeded the carrying value by 15%, and the step two calculation was not required. For the Company's remaining reporting units, the estimated fair values substantially exceeded the carrying values. Grainger monitors the operating performance of Fabory and the quarterly assessment did not indicate the presence of any goodwill impairment triggering events as of September 30, 2016. If Fabory's future earnings and cash flows projections are not achieved or economic conditions in Europe deteriorate, future impairment of Fabory's intangible assets, including goodwill, could result.