Debt (Notes)	9 Months Ended
Sep. 30, 2016
Debt Instrument [Line Items]
Debt Disclosure [Text Block]	7. DEBT 5.375% Senior Notes due 2024 On June 15, 2016, WESCO Distribution issued $350 million aggregate principal amount of 5.375% Senior Notes due 2024 (the "2024 Notes") through a private offering exempt from the registration requirements of the Securities Act of 1933, as amended. The 2024 Notes were issued at 100% of par and are governed by an indenture (the “Indenture”) entered into on June 15, 2016 among WESCO Distribution, as issuer, WESCO International, Inc., as parent guarantor, and U.S. Bank National Association, as trustee. The 2024 Notes are unsecured senior obligations of WESCO Distribution and are guaranteed on a senior unsecured basis by WESCO International, Inc. The 2024 Notes bear interest at a rate of 5.375% per annum, payable semi-annually in arrears on June 15 and December 15 of each year, commencing on December 15, 2016. The notes mature on June 15, 2024. WESCO incurred costs totaling $6.0 million to issue the 2024 Notes, which are recorded as a reduction to the carrying value of the debt. The Company used the net proceeds to redeem its 2029 Debentures on September 15, 2016. At any time on or after June 15, 2019, WESCO Distribution may redeem all or a part of the 2024 Notes. Between June 15, 2019 and June 14, 2020, WESCO Distribution may redeem all or a part of the 2024 Notes at a redemption price equal to 104.031% of the principal amount. Between June 15, 2020 and June 14, 2021, WESCO Distribution may redeem all or a part of the 2024 Notes at a redemption price equal to 102.688% of the principal amount. Between June 15, 2021 and June 14, 2022, WESCO Distribution may redeem all or a part of the 2024 Notes at a redemption price equal to 101.344% of the principal amount. On and after June 15, 2022, WESCO Distribution may redeem all or a part of the 2024 Notes at a redemption price equal to 100% of the principal amount. The Indenture governing the 2024 Notes contains customary covenants and events of default. Upon a change of control, the holders of the 2024 Notes have the right to require WESCO Distribution to repurchase all or any part of the 2024 Notes at a redemption price equal to 101% of the principal amount thereof, plus accrued and unpaid interest. 6.0% Convertible Senior Debentures due 2029 On September 15, 2016, the Company completed the redemption of its 2029 Debentures. Holders of the 2029 Debentures received cash totaling $344.8 million, which was equal to the principal amount of the then-outstanding Debentures, in addition to accrued and unpaid interest. Holders who surrendered the 2029 Debentures for conversion received 18 shares of WESCO stock for each $1,000 principal amount of 2029 Debentures converted. In total, 6,267,688 shares were issued at the redemption date closing price of WESCO’s common stock. The redemption resulted in a non-cash loss of $123.9 million, which included the write off of unamortized debt issuance costs.

7. DEBT

5.375% Senior Notes due 2024

On June 15, 2016, WESCO Distribution issued $350 million aggregate principal amount of 5.375% Senior Notes due 2024 (the "2024 Notes") through a private offering exempt from the registration requirements of the Securities Act of 1933, as amended. The 2024 Notes were issued at 100% of par and are governed by an indenture (the “Indenture”) entered into on June 15, 2016 among WESCO Distribution, as issuer, WESCO International, Inc., as parent guarantor, and U.S. Bank National Association, as trustee. The 2024 Notes are unsecured senior obligations of WESCO Distribution and are guaranteed on a senior unsecured basis by WESCO International, Inc. The 2024 Notes bear interest at a rate of 5.375% per annum, payable semi-annually in arrears on June 15 and December 15 of each year, commencing on December 15, 2016. The notes mature on June 15, 2024.

WESCO incurred costs totaling $6.0 million to issue the 2024 Notes, which are recorded as a reduction to the carrying value of the debt. The Company used the net proceeds to redeem its 2029 Debentures on September 15, 2016.

At any time on or after June 15, 2019, WESCO Distribution may redeem all or a part of the 2024 Notes. Between June 15, 2019 and June 14, 2020, WESCO Distribution may redeem all or a part of the 2024 Notes at a redemption price equal to 104.031% of the principal amount. Between June 15, 2020 and June 14, 2021, WESCO Distribution may redeem all or a part of the 2024 Notes at a redemption price equal to 102.688% of the principal amount. Between June 15, 2021 and June 14, 2022, WESCO Distribution may redeem all or a part of the 2024 Notes at a redemption price equal to 101.344% of the principal amount. On and after June 15, 2022, WESCO Distribution may redeem all or a part of the 2024 Notes at a redemption price equal to 100% of the principal amount.

The Indenture governing the 2024 Notes contains customary covenants and events of default. Upon a change of control, the holders of the 2024 Notes have the right to require WESCO Distribution to repurchase all or any part of the 2024 Notes at a redemption price equal to 101% of the principal amount thereof, plus accrued and unpaid interest.

6.0% Convertible Senior Debentures due 2029

On September 15, 2016, the Company completed the redemption of its 2029 Debentures. Holders of the 2029 Debentures received cash totaling $344.8 million, which was equal to the principal amount of the then-outstanding Debentures, in addition to accrued and unpaid interest. Holders who surrendered the 2029 Debentures for conversion received 18 shares of WESCO stock for each $1,000 principal amount of 2029 Debentures converted. In total, 6,267,688 shares were issued at the redemption date closing price of WESCO’s common stock. The redemption resulted in a non-cash loss of $123.9 million, which included the write off of unamortized debt issuance costs.