| DEBT | 6 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| DEBT |   4. DEBT
   Debt outstanding at June 30, 2013 and December 31, 2012 was as  follows: 
   Senior Credit Facility. We are party to a  $750.0  million unsecured revolving credit facility, which we refer to as  the Senior Credit Facility, with a group of financial institutions.  The Senior Credit Facility also has an accordion feature that  allows us to request an increase in the total commitment to $1.0  billion. Borrowings may be used for general corporate purposes,  including working capital, capital expenditures, acquisitions and  share repurchase programs. The Senior Credit Facility is scheduled  to expire in December 2017. Availability of the Senior Credit  Facility for borrowings is reduced by the outstanding face amount  of any letters of credit issued under the facility and, pursuant to  our existing Board of Directors authorization, by the outstanding  principal amount of our commercial paper notes. As of June 30,  2013, there were no outstanding borrowings under this facility and  $688.6  million was available for borrowing.   Commercial Paper Program. Our $750.0  million commercial paper program has been established through the  private placement of commercial paper notes from time-to-time.  Maturities of commercial paper can range from overnight to 397  days. The commercial paper program is supported by our Senior  Credit Facility and, pursuant to our existing Board of Directors  authorization, the total amount of commercial paper which may be  issued is reduced by the amount of any outstanding borrowings under  our Senior Credit Facility. At June 30, 2013, there was $60.0  million in commercial paper notes outstanding.   For additional information about our debt agreements, see Note 6 of  the Notes to Consolidated Financial Statements in our 2012 Form  10-K. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||