Legal Proceedings	9 Months Ended
Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Legal Proceedings	Legal Proceedings MSA Venture On November 10, 2015, MSA received a final decision of the Department of Energy ("DoE") contracting officer for the Mission Support Contract concluding that certain payments to MSA by DoE for the performance of IT services by Lockheed Martin Services, Inc. (“LMSI”) under a subcontract to MSA constituted alleged affiliate fees in violation of the Federal Acquisition Regulation (the "FAR"). Lockheed Martin Integrated Technology LLC (now known as Leidos Integrated Technology LLC) is a member entity of MSA. At the same time, the contracting officer advised MSA that he would not approve certain provisional fee payments to MSA pending resolution of the matters set forth in his decision. Subsequent to the contracting officer's final decision, MSA, LMSI, and Lockheed Martin Corporation received notice from the U.S. Attorney's Office for the Eastern District of Washington that the U.S. Government had initiated a False Claims Act investigation into the facts surrounding this dispute, and each of MSA, LMSI and Lockheed Martin Corporation have produced information in response to Civil Investigative Demands from the U.S. Attorney's Office. Since this issue first was raised by the DoE, MSA has asserted that the IT services performed by LMSI under a fixed price/fixed unit rate subcontract approved by the DoE meet the definition of a "commercial item" under the FAR and any profits earned on that subcontract are permissible. MSA filed an appeal of the contracting officer's decision with the Civilian Board of Contract Appeals and that appeal is pending, but has been stayed pending resolution of the False Claims Act investigation. Subsequent to the filing of MSA's appeal, the contracting officer demanded that MSA reimburse the DoE in the amount of $64 million, which was his estimate of the profits earned during the period from 2010 to 2014 by LMSI. The DoE has deferred that demand, pending resolution of the appeal, but to date the demand has not been rescinded. MSA and the other members of MSA have indicated they believe if MSA incurs a liability in this matter, then Leidos Integrated Technology, LLC is responsible to MSA for the loss. Under the terms of the Separation Agreement, Lockheed Martin has agreed to indemnify the Company for 100% of any damages in excess of $38 million up to $64 million, and 50% of any damages in excess of $64 million, with respect to claims asserted against MSA related to this matter. At September 30, 2016, the Company recorded a liability of $40 million and an indemnification asset of $2 million in the condensed consolidated balance sheets. Data Privacy Litigation The Company was previously a defendant in a putative class action, In Re: Science Applications International Corporation ("SAIC") Backup Tape Data Theft Litigation, which was a Multidistrict Litigation ("MDL") action in the U.S. District Court for the District of Columbia relating to the theft of computer backup tapes from a vehicle of a company employee. In May 2014, the District Court dismissed all but two plaintiffs from the MDL action. In June 2014, Leidos and its co-defendant, TRICARE, entered into settlement agreements with the remaining two plaintiffs who subsequently dismissed their claims with prejudice. On September 20, 2014, the Company was named as a defendant in a putative class action, Martin Fernandez, on Behalf Of Himself And All Other Similarly Situated v. Leidos, Inc. in the Eastern District Court of California, related to the same theft of computer backup tapes. The recent complaint includes allegations of violations of the California Confidentiality of Medical Information Act, the California Unfair Competition Law and other claims. On August 28, 2015, the Court dismissed all claims brought by the Plaintiff against the Company. Plaintiff filed a notice of appeal of this dismissal on November 17, 2015, to the United States Court of Appeals for the Ninth Circuit where the appeal remains pending. Plaintiff filed his appellate brief on May 6, 2016. Leidos filed its response on July 6, 2016 and Plaintiff filed his reply on August 19, 2016. Securities Litigation Between February and April 2012, alleged stockholders filed three putative securities class actions. One case was withdrawn and two cases were consolidated in the U.S. District Court for the Southern District of New York in In Re: SAIC, Inc. Securities Litigation. The consolidated securities complaint named as defendants the Company, a former chief financial officer, two former chief executive officers, a former group president and the former program manager on the Company's contract to develop and implement an automated time and attendance and workforce management system for certain agencies of the City of New York ("CityTime") and was filed purportedly on behalf of all purchasers of the Company's common stock from April 11, 2007, through September 1, 2011. The consolidated securities complaint asserted claims under Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 based on allegations that the Company and individual defendants made misleading statements or omissions about the Company’s revenues, operating income and internal controls in connection with disclosures relating to the CityTime project. The plaintiffs sought to recover from the Company and the individual defendants an unspecified amount of damages class members allegedly incurred by buying Leidos' stock at an inflated price. On October 1, 2013, the District Court dismissed many claims in the complaint with prejudice and on January 30, 2014, the District Court entered an order dismissing all remaining claims with prejudice and without leave to replead. The plaintiffs moved to vacate the District Court's judgment or obtain relief from the judgment and for leave to file an amended complaint. On September 30, 2014, the District Court denied plaintiffs' motions. The plaintiffs then appealed to the United States Court of Appeals for the Second Circuit. On March 29, 2016, the Second Circuit issued an opinion affirming in part, and vacating in part, the District Court's ruling. In particular, the Second Circuit held that the plaintiffs should be permitted to pursue omissions claims against the Company with respect to the annual report the Company filed on Form 10-K on March 25, 2011; the Second Circuit affirmed dismissal of all other claims, including all the claims against the individual defendants. The Company petitioned the Second Circuit on April 12, 2016 to rehear the appeal, which was denied on August 2, 2016. The case is now remanded to the District Court for further proceedings on plaintiffs' claim. Greek Government Contract Background and Arbitration. In May 2003, the Company entered into a firm-fixed-price contract with the Hellenic Republic of Greece (the "Customer") to provide a Command, Control, Communications, Coordination and Integration System (the "System") to support the 2004 Athens Summer Olympic Games (the "Olympics") and to serve as the security system for the Customer’s public order departments following completion of the Olympics. In November 2008, the Customer accepted the System in writing pursuant to the requirements of the contract. At the time, the Customer determined that the System substantially complied with the terms of the contract and accepted the System with certain alleged minor omissions and deviations. Upon System acceptance, the Company invoiced the Customer for $15 million, representing the undisputed portion of the contract balance owed to the Company. The Customer has not paid this final invoice. In June 2009, the Company initiated arbitration before the International Chamber of Commerce against the Customer seeking damages for breaches of contract by the Customer. In July 2013, the Company received an arbitral award for $44 million. The Customer has yet to satisfy the arbitral award. The Company is pursuing an enforcement action in U.S. District Court for the District of Columbia. In September 2013, the Customer filed a petition in a Greek court seeking to nullify the arbitral award and to stay enforcement of the award in Greece. A hearing on the Customer's nullification request was held in Greece in April 2014. The parties agreed to a stay of the Company's enforcement action in U.S. District Court until the Greek court issued a ruling on the Customer's nullification request. In June 2014, the Athens Court of Appeals annulled the arbitral award. The Company appealed the annulment decision to the Supreme Court of Greece in January 2015 to have the arbitral award reinstated. On September 22, 2016, the Supreme Court of Greece issued a written decision upholding the Company’s appeal and remanding the case back to the appeals court for further proceedings consistent with the Supreme Court’s decision. The Company is continuing to pursue enforcement of the award in the U.S. District Court as is still its right under U.S. and international law. The outcomes of the appeal in Greece and the Company's pending enforcement action are uncertain. Financial Status and Contingencies. As a result of the significant uncertainties on this contract, the Company converted to the completed-contract method of accounting and ceased recognizing revenues for the System development portion of this contract in fiscal 2006. No profits or losses were recorded on the Greek contract for the quarter and nine months ended September 30, 2016, and October 2, 2015. As of September 30, 2016, the Company has recorded $123 million of losses under the Greek contract, reflecting the Company’s estimated total cost to complete the System, assuming the Greek contract value was limited to the cash received to date. Based on the complex nature of this contractual situation and the difficulties encountered to date, significant uncertainties exist and the Company is unable to reliably estimate the ultimate outcome. The Company may reverse a portion of the losses from the Greek contract if it receives payments as provided in the arbitral award. As of September 30, 2016, the Company's net balance sheet exposure for the Greek contract was $2 million. The Company has $28 million for value added tax ("VAT") included in the arbitration claim of which this amount was substantially awarded in the arbitral award. The Company has paid a certain amount of VAT and believes it is entitled to recover either as a payment from the arbitral award or as a refund from the taxing authorities. This amount paid is recorded as a receivable as of September 30, 2016, and is part of the net balance sheet exposure. If the Customer fails to pay the outstanding VAT amounts through the arbitral award or the Company is unable to recover these amounts as a refund from the taxing authorities, the Company’s total losses on the Greek contract could increase. The Company has met certain advance payment and performance bonding requirements through the issuance of euro-denominated standby letters of credit. As of September 30, 2016, there were $4 million in standby letters of credit outstanding relating to the support and maintenance of the System. In the arbitration, the Company was awarded but has not received $21 million representing the amounts drawn by the Customer in fiscal 2011 on certain standby letters of credit as well as damages. The principal subcontractor has provided to the Company euro-denominated standby letters of credit in the amount of $18 million as of September 30, 2016, of which $16 million relates to the delivery of the System. The Company may draw on the subcontractor’s standby letters of credit under certain circumstances by providing a statement to the responsible bank that the subcontractor has not fulfilled its obligations under the subcontract. Other The Company is also involved in various claims and lawsuits arising in the normal conduct of its business, none of which, in the opinion of the Company’s management, based upon current information, will likely have a material adverse effect on the Company’s condensed consolidated financial position, results of operations, or cash flows.

Legal Proceedings

MSA Venture

On November 10, 2015, MSA received a final decision of the Department of Energy ("DoE") contracting officer for the Mission Support Contract concluding that certain payments to MSA by DoE for the performance of IT services by Lockheed Martin Services, Inc. (“LMSI”) under a subcontract to MSA constituted alleged affiliate fees in violation of the Federal Acquisition Regulation (the "FAR"). Lockheed Martin Integrated Technology LLC (now known as Leidos Integrated Technology LLC) is a member entity of MSA. At the same time, the contracting officer advised MSA that he would not approve certain provisional fee payments to MSA pending resolution of the matters set forth in his decision. Subsequent to the contracting officer's final decision, MSA, LMSI, and Lockheed Martin Corporation received notice from the U.S. Attorney's Office for the Eastern District of Washington that the U.S. Government had initiated a False Claims Act investigation into the facts surrounding this dispute, and each of MSA, LMSI and Lockheed Martin Corporation have produced information in response to Civil Investigative Demands from the U.S. Attorney's Office. Since this issue first was raised by the DoE, MSA has asserted that the IT services performed by LMSI under a fixed price/fixed unit rate subcontract approved by the DoE meet the definition of a "commercial item" under the FAR and any profits earned on that subcontract are permissible. MSA filed an appeal of the contracting officer's decision with the Civilian Board of Contract Appeals and that appeal is pending, but has been stayed pending resolution of the False Claims Act investigation. Subsequent to the filing of MSA's appeal, the contracting officer demanded that MSA reimburse the DoE in the amount of $64 million, which was his estimate of the profits earned during the period from 2010 to 2014 by LMSI. The DoE has deferred that demand, pending resolution of the appeal, but to date the demand has not been rescinded. MSA and the other members of MSA have indicated they believe if MSA incurs a liability in this matter, then Leidos Integrated Technology, LLC is responsible to MSA for the loss. Under the terms of the Separation Agreement, Lockheed Martin has agreed to indemnify the Company for 100% of any damages in excess of $38 million up to $64 million, and 50% of any damages in excess of $64 million, with respect to claims asserted against MSA related to this matter. At September 30, 2016, the Company recorded a liability of $40 million and an indemnification asset of $2 million in the condensed consolidated balance sheets.

Data Privacy Litigation

The Company was previously a defendant in a putative class action, In Re: Science Applications International Corporation ("SAIC") Backup Tape Data Theft Litigation, which was a Multidistrict Litigation ("MDL") action in the U.S. District Court for the District of Columbia relating to the theft of computer backup tapes from a vehicle of a company employee. In May 2014, the District Court dismissed all but two plaintiffs from the MDL action. In June 2014, Leidos and its co-defendant, TRICARE, entered into settlement agreements with the remaining two plaintiffs who subsequently dismissed their claims with prejudice.

On September 20, 2014, the Company was named as a defendant in a putative class action, Martin Fernandez, on Behalf Of Himself And All Other Similarly Situated v. Leidos, Inc. in the Eastern District Court of California, related to the same theft of computer backup tapes. The recent complaint includes allegations of violations of the California Confidentiality of Medical Information Act, the California Unfair Competition Law and other claims. On August 28, 2015, the Court dismissed all claims brought by the Plaintiff against the Company. Plaintiff filed a notice of appeal of this dismissal on November 17, 2015, to the United States Court of Appeals for the Ninth Circuit where the appeal remains pending. Plaintiff filed his appellate brief on May 6, 2016. Leidos filed its response on July 6, 2016 and Plaintiff filed his reply on August 19, 2016.

Securities Litigation

Between February and April 2012, alleged stockholders filed three putative securities class actions. One case was withdrawn and two cases were consolidated in the U.S. District Court for the Southern District of New York in In Re: SAIC, Inc. Securities Litigation. The consolidated securities complaint named as defendants the Company, a former chief financial officer, two former chief executive officers, a former group president and the former program manager on the Company's contract to develop and implement an automated time and attendance and workforce management system for certain agencies of the City of New York ("CityTime") and was filed purportedly on behalf of all purchasers of the Company's common stock from April 11, 2007, through September 1, 2011. The consolidated securities complaint asserted claims under Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 based on allegations that the Company and individual defendants made misleading statements or omissions about the Company’s revenues, operating income and internal controls in connection with disclosures relating to the CityTime project. The plaintiffs sought to recover from the Company and the individual defendants an unspecified amount of damages class members allegedly incurred by buying Leidos' stock at an inflated price. On October 1, 2013, the District Court dismissed many claims in the complaint with prejudice and on January 30, 2014, the District Court entered an order dismissing all remaining claims with prejudice and without leave to replead. The plaintiffs moved to vacate the District Court's judgment or obtain relief from the judgment and for leave to file an amended complaint. On September 30, 2014, the District Court denied plaintiffs' motions. The plaintiffs then appealed to the United States Court of Appeals for the Second Circuit. On March 29, 2016, the Second Circuit issued an opinion affirming in part, and vacating in part, the District Court's ruling. In particular, the Second Circuit held that the plaintiffs should be permitted to pursue omissions claims against the Company with respect to the annual report the Company filed on Form 10-K on March 25, 2011; the Second Circuit affirmed dismissal of all other claims, including all the claims against the individual defendants. The Company petitioned the Second Circuit on April 12, 2016 to rehear the appeal, which was denied on August 2, 2016. The case is now remanded to the District Court for further proceedings on plaintiffs' claim.

Greek Government Contract

Background and Arbitration. In May 2003, the Company entered into a firm-fixed-price contract with the Hellenic Republic of Greece (the "Customer") to provide a Command, Control, Communications, Coordination and Integration System (the "System") to support the 2004 Athens Summer Olympic Games (the "Olympics") and to serve as the security system for the Customer’s public order departments following completion of the Olympics.

In November 2008, the Customer accepted the System in writing pursuant to the requirements of the contract. At the time, the Customer determined that the System substantially complied with the terms of the contract and accepted the System with certain alleged minor omissions and deviations. Upon System acceptance, the Company invoiced the Customer for $15 million, representing the undisputed portion of the contract balance owed to the Company. The Customer has not paid this final invoice.

In June 2009, the Company initiated arbitration before the International Chamber of Commerce against the Customer seeking damages for breaches of contract by the Customer. In July 2013, the Company received an arbitral award for $44 million. The Customer has yet to satisfy the arbitral award. The Company is pursuing an enforcement action in U.S. District Court for the District of Columbia. In September 2013, the Customer filed a petition in a Greek court seeking to nullify the arbitral award and to stay enforcement of the award in Greece. A hearing on the Customer's nullification request was held in Greece in April 2014. The parties agreed to a stay of the Company's enforcement action in U.S. District Court until the Greek court issued a ruling on the Customer's nullification request. In June 2014, the Athens Court of Appeals annulled the arbitral award. The Company appealed the annulment decision to the Supreme Court of Greece in January 2015 to have the arbitral award reinstated. On September 22, 2016, the Supreme Court of Greece issued a written decision upholding the Company’s appeal and remanding the case back to the appeals court for further proceedings consistent with the Supreme Court’s decision. The Company is continuing to pursue enforcement of the award in the U.S. District Court as is still its right under U.S. and international law. The outcomes of the appeal in Greece and the Company's pending enforcement action are uncertain.

Financial Status and Contingencies. As a result of the significant uncertainties on this contract, the Company converted to the completed-contract method of accounting and ceased recognizing revenues for the System development portion of this contract in fiscal 2006. No profits or losses were recorded on the Greek contract for the quarter and nine months ended September 30, 2016, and October 2, 2015. As of September 30, 2016, the Company has recorded $123 million of losses under the Greek contract, reflecting the Company’s estimated total cost to complete the System, assuming the Greek contract value was limited to the cash received to date. Based on the complex nature of this contractual situation and the difficulties encountered to date, significant uncertainties exist and the Company is unable to reliably estimate the ultimate outcome. The Company may reverse a portion of the losses from the Greek contract if it receives payments as provided in the arbitral award. As of September 30, 2016, the Company's net balance sheet exposure for the Greek contract was $2 million.

The Company has $28 million for value added tax ("VAT") included in the arbitration claim of which this amount was substantially awarded in the arbitral award. The Company has paid a certain amount of VAT and believes it is entitled to recover either as a payment from the arbitral award or as a refund from the taxing authorities. This amount paid is recorded as a receivable as of September 30, 2016, and is part of the net balance sheet exposure. If the Customer fails to pay the outstanding VAT amounts through the arbitral award or the Company is unable to recover these amounts as a refund from the taxing authorities, the Company’s total losses on the Greek contract could increase.

The Company has met certain advance payment and performance bonding requirements through the issuance of euro-denominated standby letters of credit. As of September 30, 2016, there were $4 million in standby letters of credit outstanding relating to the support and maintenance of the System. In the arbitration, the Company was awarded but has not received $21 million representing the amounts drawn by the Customer in fiscal 2011 on certain standby letters of credit as well as damages. The principal subcontractor has provided to the Company euro-denominated standby letters of credit in the amount of $18 million as of September 30, 2016, of which $16 million relates to the delivery of the System. The Company may draw on the subcontractor’s standby letters of credit under certain circumstances by providing a statement to the responsible bank that the subcontractor has not fulfilled its obligations under the subcontract.

Other

The Company is also involved in various claims and lawsuits arising in the normal conduct of its business, none of which, in the opinion of the Company’s management, based upon current information, will likely have a material adverse effect on the Company’s condensed consolidated financial position, results of operations, or cash flows.