INCOME TAXES	9 Months Ended
Sep. 30, 2012
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The effective tax rate for the three months ended September 30, 2012 and 2011 was 29.9% and 29.7% respectively, and the effective tax rate for the nine months ended September 30, 2012 and 2011 was 29.8% and 29.2%, respectively. WESCO’s three and nine month effective tax rates are lower than the federal statutory rate of 35% primarily due to benefits resulting from the recapitalization of Canadian operations, which are partially offset by nondeductible expenses, state taxes and foreign rate differences. The effective tax rate for the nine months ended September 30, 2012 and 2011 reflects beneficial discrete adjustments totaling $3.2 million and $2.1 million, respectively, primarily related to state taxes and changes in uncertain tax positions. The beneficial discrete adjustments in the effective tax rate for the three months ended September 30, 2012 and 2011 were immaterial. The total amount of net unrecognized tax benefits were $20.1 million and $20.9 million as of September 30, 2012 and December 31, 2011, respectively. A related deferred tax asset in the amount of $23.1 million excluding interest was recorded in 2011. If these tax benefits were recognized in the consolidated financial statements, the portion of these amounts that would reduce WESCO’s effective tax rate would be $20.2 million and $19.7 million, respectively. This amount would be offset by a decrease in the corresponding deferred tax asset discussed above. During the next twelve months, it is reasonably possible that the amount of unrecognized tax benefits will decrease by as much as $15.5 million (all of which will be offset by the reversal of a deferred tax asset) due to possible resolution of federal, state and/or foreign tax examinations and/or the expiration of statutes of limitations. Management does not expect this decrease to have an impact on the effective tax rate. WESCO records interest related to uncertain tax positions as a part of interest expense in the consolidated statement of income. Penalties are recognized as part of income tax expense. As of September 30, 2012 and December 31, 2011, WESCO had an accrued liability for interest related to uncertain tax positions of $8.1 million and $11.4 million, respectively. During the nine months ended September 30, 2012, accrued interest and net interest expense decreased by $3.3 million primarily as a result of a favorable Internal Revenue Service appeals settlement in the first quarter of 2012 related to the years 2000 to 2006. There were no material penalties recorded during the three or nine months ended September 30, 2012 or 2011.

INCOME TAXES

9 Months Ended

Sep. 30, 2012

The effective tax rate for the three months ended September 30, 2012 and 2011 was 29.9% and 29.7% respectively, and the effective tax rate for the nine months ended September 30, 2012 and 2011 was 29.8% and 29.2%, respectively. WESCO’s three and nine month effective tax rates are lower than the federal statutory rate of 35% primarily due to benefits resulting from the recapitalization of Canadian operations, which are partially offset by nondeductible expenses, state taxes and foreign rate differences. The effective tax rate for the nine months ended September 30, 2012 and 2011 reflects beneficial discrete adjustments totaling $3.2 million and $2.1 million, respectively, primarily related to state taxes and changes in uncertain tax positions. The beneficial discrete adjustments in the effective tax rate for the three months ended September 30, 2012 and 2011 were immaterial.

The total amount of net unrecognized tax benefits were $20.1 million and $20.9 million as of September 30, 2012 and December 31, 2011, respectively. A related deferred tax asset in the amount of $23.1 million excluding interest was recorded in 2011. If these tax benefits were recognized in the consolidated financial statements, the portion of these amounts that would reduce WESCO’s effective tax rate would be $20.2 million and $19.7 million, respectively. This amount would be offset by a decrease in the corresponding deferred tax asset discussed above.

During the next twelve months, it is reasonably possible that the amount of unrecognized tax benefits will decrease by as much as $15.5 million (all of which will be offset by the reversal of a deferred tax asset) due to possible resolution of federal, state and/or foreign tax examinations and/or the expiration of statutes of limitations. Management does not expect this decrease to have an impact on the effective tax rate.

WESCO records interest related to uncertain tax positions as a part of interest expense in the consolidated statement of income. Penalties are recognized as part of income tax expense. As of September 30, 2012 and December 31, 2011, WESCO had an accrued liability for interest related to uncertain tax positions of $8.1 million and $11.4 million, respectively. During the nine months ended September 30, 2012, accrued interest and net interest expense decreased by $3.3 million primarily as a result of a favorable Internal Revenue Service appeals settlement in the first quarter of 2012 related to the years 2000 to 2006. There were no material penalties recorded during the three or nine months ended September 30, 2012 or 2011.