XML 36 R21.htm IDEA: XBRL DOCUMENT
v3.8.0.1

CAPITAL STOCK | 12 Months Ended
--- | ---
Dec. 31, 2017
CAPITAL STOCK [Abstract] |
CAPITAL STOCK | CAPITAL STOCK The Company had no shares of preferred stock outstanding as of December 31, 2017 and 2016. The activity related to outstanding common stock and common stock held in treasury was as follows:
| 2017 |  | 2016 |  | 2015
| Outstanding Common Stock | Treasury Stock |  | Outstanding Common Stock | Treasury Stock |  | Outstanding Common Stock | Treasury Stock
Balance at beginning of period | 58,804,314 |  | 50,854,905 |  |  | 62,028,708 |  | 47,630,511 |  |  | 67,432,041 |  | 42,227,178 |
Exercise of stock options | 407,542 |  | (407,542 | ) |  | 315,171 |  | (315,171 | ) |  | 580,947 |  | (580,947 | )
Settlement of restricted stock units, net of 36,585, 41,128 and 73,496 shares retained, respectively | 103,331 |  | (103,331 | ) |  | 78,310 |  | (78,310 | ) |  | 145,757 |  | (145,757 | )
Settlement of performance share units, net of 9,334, 6,765 and 9,971 shares retained, respectively | 13,978 |  | (13,978 | ) |  | 11,806 |  | (11,806 | ) |  | 15,956 |  | (15,956 | )
Purchase of treasury shares | (3,000,302 | ) | 3,000,302 |  |  | (3,629,681 | ) | 3,629,681 |  |  | (6,145,993 | ) | 6,145,993 |
Balance at end of period | 56,328,863 |  | 53,330,356 |  |  | 58,804,314 |  | 50,854,905 |  |  | 62,028,708 |  | 47,630,511 |

X
- Definition CAPITAL STOCK [Abstract] + References No definition available. + Details
Name: | gww_CapitalStockAbstract
Namespace Prefix: | gww_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Disclosure of the activity of outstanding common stock and common stock held in treasury. + References No definition available. + Details
Name: | gww_CapitalStockTextBlock
Namespace Prefix: | gww_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration