contractual obligations in 2011 , we issued $ 1200 million of senior notes and entered into the credit facility with third-party lenders in the amount of $ 1225 million . as of december 31 , 2011 , total outstanding long-term debt was $ 1859 million , consisting of these senior notes and the credit facility , in addition to $ 105 million of third party debt that remained outstanding subsequent to the spin-off . in connection with the spin-off , we entered into a transition services agreement with northrop grumman , under which northrop grumman or certain of its subsidiaries provides us with certain services to help ensure an orderly transition following the distribution . under the transition services agreement , northrop grumman provides , for up to 12 months following the spin-off , certain enterprise shared services ( including information technology , resource planning , financial , procurement and human resource services ) , benefits support services and other specified services . the original term of the transition services agreement ends on march 31 , 2012 , although we have the right to and have cancelled certain services as we transition to new third-party providers . the services provided by northrop grumman are charged to us at cost , and a limited number of these services may be extended for a period of approximately six months to allow full information systems transition . see note 20 : related party transactions and former parent company equity in item 8 . in connection with the spin-off , we entered into a tax matters agreement with northrop grumman ( the 201ctax matters agreement 201d ) that governs the respective rights , responsibilities and obligations of northrop grumman and us after the spin-off with respect to tax liabilities and benefits , tax attributes , tax contests and other tax sharing regarding u.s . federal , state , local and foreign income taxes , other taxes and related tax returns . we have several liabilities with northrop grumman to the irs for the consolidated u.s . federal income taxes of the northrop grumman consolidated group relating to the taxable periods in which we were part of that group . however , the tax matters agreement specifies the portion of this tax liability for which we will bear responsibility , and northrop grumman has agreed to indemnify us against any amounts for which we are not responsible . the tax matters agreement also provides special rules for allocating tax liabilities in the event that the spin-off , together with certain related transactions , is not tax-free . see note 20 : related party transactions and former parent company equity in item 8 . we do not expect either the transition services agreement or the tax matters agreement to have a significant impact on our financial condition and results of operations . the following table presents our contractual obligations as of december 31 , 2011 , and the related estimated timing of future cash payments : ( $ in millions ) total 2012 2013 - 2014 2015 - 2016 2017 and beyond .
what portion of the long-term debt is included in the section of current liabilities on the balance sheet as of december 31 , 2011?
( 1 ) interest payments include interest on $ 554 million of variable interest rate debt calculated based on interest rates at december 31 , 2011 . ( 2 ) a 201cpurchase obligation 201d is defined as an agreement to purchase goods or services that is enforceable and legally binding on us and that specifies all significant terms , including : fixed or minimum quantities to be purchased ; fixed , minimum , or variable price provisions ; and the approximate timing of the transaction . these amounts are primarily comprised of open purchase order commitments to vendors and subcontractors pertaining to funded contracts . ( 3 ) other long-term liabilities primarily consist of total accrued workers 2019 compensation reserves , deferred compensation , and other miscellaneous liabilities , of which $ 201 million is the current portion of workers 2019 compensation liabilities . it excludes obligations for uncertain tax positions of $ 9 million , as the timing of the payments , if any , cannot be reasonably estimated . the above table excludes retirement related contributions . in 2012 , we expect to make minimum and discretionary contributions to our qualified pension plans of approximately $ 153 million and $ 65 million , respectively , exclusive of any u.s . government recoveries . we will continue to periodically evaluate whether to make additional discretionary contributions . in 2012 , we expect to make $ 35 million in contributions for our other postretirement plans , exclusive of any .