Commitments and Contingencies Commitments The following table summarizes contractual obligations and commitments as of October30, 2016 (in millions): Fiscal Year Total 2017 2018 2019 2020 2021 Thereafter Debt principal, interest and fees $ 15,828 $ 850 $ 965 $ 1,019 $ 3,684 $ 2,757 $ 6,553 Purchase commitments 1,508 1,455 53     Other contractual commitments 390 152 106 79 49 4  Operating lease obligations 446 144 116 69 43 18 56 Pension plan contributions 37 37      Total $ 18,209 $ 2,638 $ 1,240 $ 1,167 $ 3,776 $ 2,779 $ 6,609 Debt Principal, Interest and Fees. Represents principal, interest and commitment fees payable on borrowings and credit facilities under the 2016 Credit Agreement and the Senior Notes. Purchase Commitments. Represents unconditional purchase obligations that include agreements to purchase goods or services, primarily inventory, that are enforceable and legally binding on us and that specify all significant terms, including fixed or minimum quantities to be purchased, fixed, minimum or variable price provisions, and the approximate timing of the transaction. Purchase obligations exclude agreements that are cancelable without penalty. Cancellation for outstanding purchase orders for capital expenditures in connection with internal fabrication facility expansion and construction of our new campuses is generally allowed but requires payment of all costs incurred through the date of cancellation and, therefore, cancelable purchase orders for these capital expenditures are included in the table above. Other Contractual Commitments. Represents amounts payable pursuant to agreements related to IT, human resources, financial infrastructure outsourcing services and other service agreements. Operating Lease Obligations. Represents real property and equipment leased from third parties under non-cancelable operating leases. Rent expense was $229 million , $77 million and $42 million for fiscal years 2016 , 2015 and 2014 , respectively. Pension Plan Contributions. Represents our planned mini