Commitments and Contingencies (Notes)	3 Months Ended
Mar. 31, 2013
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies [Text Block]	Commitments and Contingencies Commitments Operating Leases The Company leases its facilities and certain equipment under non-cancelable operating leases that expire at various dates through November 30, 2022. Certain leases require the Company to pay variable costs such as taxes, maintenance, and insurance and include renewal options and escalation clauses. Future minimum payments under the non-cancelable operating leases totaled $252.8 million as of March 31, 2013. Rent expense was $13.7 million and $15.7 million for the three months ended March 31, 2013 and March 31, 2012, respectively. Purchase Commitments In order to reduce manufacturing lead times and ensure adequate component supply, the Company enters into agreements with contract manufacturers and certain suppliers to procure inventory based on the Company's requirements. A significant portion of the Company's purchase commitments arising from these agreements consists of firm and non-cancelable commitments. These purchase commitments totaled $459.1 million as of March 31, 2013. The Company establishes a liability in connection with these purchase commitments related to carrying charges, quantities in excess of our demand forecasts, or obsolete materials charges for materials purchased by contract manufacturers to meet the Company’s forecast or customer orders. As of March 31, 2013, the Company accrued $24.0 million based on its estimate of such charges. Long-Term Debt and Interest Payment on Long-Term Debt As of March 31, 2013, the Company held long-term debt consisting of senior notes with a carrying value of $999.2 million. Of these Notes, $300.0 million will mature in 2016 and bears interest at a fixed rate of 3.10%, $300.0 million will mature in 2021 and bears interest at a fixed rate of 4.60%, and $400.0 million will mature in 2041 and bears interest at a fixed rate of 5.95%. Interest on the Notes is payable semiannually. See Note 10, Long-Term Debt and Financing, for further discussion of the Company's long-term debt. Other Contractual Obligations As of March 31, 2013, other contractual obligations primarily consisted of $94.4 million in indemnity-related and service related escrows, required by certain asset purchases and acquisitions completed in 2005, 2010, 2011, and 2012, campus build-out obligations of $47.5 million, and other miscellaneous commitments of $14.7 million. Tax Liabilities As of March 31, 2013, the Company had $87.1 million included in long-term incomes taxes payable in the Condensed Consolidated Balance Sheets for unrecognized tax positions. At this time, the Company is unable to make a reasonably reliable estimate of the timing of payments related to this amount due to uncertainties in the timing of tax audit outcomes. Guarantees The Company enters into agreements with customers that contain indemnification provisions relating to potential situations where claims could be alleged that the Company’s products infringe the intellectual property rights of a third-party. The Company also has financial guarantees consisting of guarantees of product and service performance, guarantees related to third-party customer-financing arrangements, customs and duties guarantees, and standby letters of credit for certain lease facilities. As of March 31, 2013 and December 31, 2012, the Company had $11.7 million and $12.6 million, respectively, in bank guarantees and standby letters of credit related to these financial guarantees. Legal Proceedings The Company is involved in disputes, litigation, and other legal actions, including, but not limited to, the matters described below. The Company is aggressively defending its current litigation matters, and while there can be no assurances and the outcome of these matters is currently not determinable, the Company currently believes that there are no existing claims or proceedings that are likely to have a material adverse effect on its financial position. There are many uncertainties associated with any litigation and these actions or other third-party claims against the Company may cause the Company to incur costly litigation and/or substantial settlement charges. In addition, the resolution of any intellectual property litigation may require the Company to make royalty payments, which could adversely affect gross margins in future periods. If any of those events were to occur, the Company's business, financial condition, results of operations, and cash flows could be adversely affected. The actual liability in any such matters may be materially different from the Company's estimates, if any, which could result in the need to adjust the liability and record additional expenses. Unless otherwise noted below, during the period presented, we have not: recorded any accrual for loss contingencies associated with such legal proceedings; determined that an unfavorable outcome is probable or reasonably possible; or determined that the amount or range of any possible loss is reasonably estimable. 2011 Federal Securities Class Action On August 15, 2011, a purported securities class action lawsuit, captioned City of Royal Oak Retirement System v. Juniper Networks, Inc., et al., Case No. 11-cv-04003-LHK, was filed in the United States District Court for the Northern District of California naming the Company and certain of its officers and directors as defendants. The complaint alleges that the defendants made false and misleading statements regarding the Company's business and prospects. Plaintiffs seek an unspecified amount of monetary damages on behalf of the purported class. On January 9, 2012 the Court appointed City of Omaha Police and Fire Retirement System and City of Bristol Pension Fund as lead plaintiffs. Lead plaintiffs allege that defendants made false and misleading statements about the Company's business and future prospects, and failed to adequately disclose the impact of certain changes in accounting rules. Lead plaintiffs purport to assert claims for violations of Sections 10 (b), 20(a) and 20A of the Securities Exchange Act of 1934 and SEC Rule 10b-5 on behalf of those who purchased or otherwise acquired Juniper Networks' common stock between July 20, 2010 and July 26, 2011, inclusive. On March 14, 2012, Defendants filed motions to dismiss lead plaintiffs' amended complaint. On July 23, 2012, the Court issued an order dismissing the action and giving lead plaintiffs leave to file an amended complaint. Lead plaintiffs filed their second amended complaint on August 20, 2012. Defendants filed a motion to dismiss the second amended complaint on September 17, 2012, and lead plaintiffs filed their opposition on October 22, 2012. Defendants filed their reply brief on November 8, 2012. A hearing on the motion to dismiss is scheduled for May 16, 2013. 2011 California State Derivative Lawsuits Between August 22 and September 9, 2011, four purported shareholder derivative actions were filed in the Superior Court of the State of California, County of Santa Clara, naming certain of the Company's officers and directors as defendants. The Company is named only as a nominal defendant in the actions. The actions were consolidated as In re Juniper Networks, Inc. Shareholder Litigation, Case No. 1-11-CV-207701 (Lead Case), by order dated September 12, 2011. The complaints are generally based upon the disclosures and alleged omissions challenged in the securities class action. The complaints purport to assert claims against the defendants for breach of fiduciary duties, unjust enrichment, abuse of control, gross mismanagement, and waste of corporate assets. The complaints seek, among other relief, damages in an unspecified amount, restitution, and attorneys' fees and costs. On March 8, 2012, the Company filed a motion to stay the action until resolution of the federal securities class action discussed above, and also filed a demurrer seeking to dismiss the action for the reason that plaintiffs lack standing. The plaintiffs filed oppositions to both motions on April 5, 2012. Defendants filed reply briefs on May 7, 2012. At a hearing on July 27, 2012, the Court ordered that the actions be stayed until such time as the federal court issues an order denying a motion to dismiss in the securities class action, City of Omaha Police and Fire Retirement System v. Juniper Networks, Inc. et al., Case No. CV-11-4003-LHK. The Court deferred deciding the demurrer pending the stay. 2011 Federal Derivative Lawsuit On September 27, 2011 and December 28, 2011, two purported shareholder derivative actions, captioned Ratinova v. Johnson, et al., Case No. 11-cv-04792 and Lisa E. Coppola, ERA v. Johnson, et al., Case No. 11-cv-06667, respectively, were filed in the United States District Court for the Northern District of California naming certain of the Company's officers and directors as defendants. The Company is named only as a nominal defendant in the action. Like the state derivative actions, the federal derivative lawsuits are generally based upon the disclosures and alleged omissions challenged in the securities class action. The complaints purport to assert claims against the defendants for breach of fiduciary duties and unjust enrichment. The complaints seek, among other relief, damages in an unspecified amount, restitution, and attorneys' fees and costs. By order dated January 30, 2012, the Court consolidated the actions as In re Juniper Networks, Inc. Shareholder Derivative Litigation, Master File No. 11-cv-04792-LHK. On February 3, 2012, the parties filed a stipulation in which the parties requested that the Court stay the action until such time as the Court entered an order denying a motion to dismiss in the related federal securities class action described above. On February 6, 2012, the Court granted the parties' stipulation. IRS Notices of Proposed Adjustments The Company is currently under examination by the IRS for the 2007 through 2009 tax years. In March 2013, the Company executed a closing agreement with the Appeals Division of the IRS related to its intercompany R&D cost sharing arrangement for the license of intangibles acquired in 2004, 2005 and 2006. The Company reached a final resolution with the IRS on all proposed adjustments for all tax years through 2006, which resulted in a settlement of approximately $20.9 million, including interest.

Commitments and Contingencies

Commitments

Operating Leases

The Company leases its facilities and certain equipment under non-cancelable operating leases that expire at various dates through November 30, 2022. Certain leases require the Company to pay variable costs such as taxes, maintenance, and insurance and include renewal options and escalation clauses. Future minimum payments under the non-cancelable operating leases totaled $252.8 million as of March 31, 2013. Rent expense was $13.7 million and $15.7 million for the three months ended March 31, 2013 and March 31, 2012, respectively.

Purchase Commitments

In order to reduce manufacturing lead times and ensure adequate component supply, the Company enters into agreements with contract manufacturers and certain suppliers to procure inventory based on the Company's requirements. A significant portion of the Company's purchase commitments arising from these agreements consists of firm and non-cancelable commitments. These purchase commitments totaled $459.1 million as of March 31, 2013. The Company establishes a liability in connection with these purchase commitments related to carrying charges, quantities in excess of our demand forecasts, or obsolete materials charges for materials purchased by contract manufacturers to meet the Company’s forecast or customer orders. As of March 31, 2013, the Company accrued $24.0 million based on its estimate of such charges.

Long-Term Debt and Interest Payment on Long-Term Debt

As of March 31, 2013, the Company held long-term debt consisting of senior notes with a carrying value of $999.2 million. Of these Notes, $300.0 million will mature in 2016 and bears interest at a fixed rate of 3.10%, $300.0 million will mature in 2021 and bears interest at a fixed rate of 4.60%, and $400.0 million will mature in 2041 and bears interest at a fixed rate of 5.95%. Interest on the Notes is payable semiannually. See Note 10, Long-Term Debt and Financing, for further discussion of the Company's long-term debt.

Other Contractual Obligations

As of March 31, 2013, other contractual obligations primarily consisted of $94.4 million in indemnity-related and service related escrows, required by certain asset purchases and acquisitions completed in 2005, 2010, 2011, and 2012, campus build-out obligations of $47.5 million, and other miscellaneous commitments of $14.7 million.

Tax Liabilities

As of March 31, 2013, the Company had $87.1 million included in long-term incomes taxes payable in the Condensed Consolidated Balance Sheets for unrecognized tax positions. At this time, the Company is unable to make a reasonably reliable estimate of the timing of payments related to this amount due to uncertainties in the timing of tax audit outcomes.

Guarantees

The Company enters into agreements with customers that contain indemnification provisions relating to potential situations where claims could be alleged that the Company’s products infringe the intellectual property rights of a third-party. The Company also has financial guarantees consisting of guarantees of product and service performance, guarantees related to third-party customer-financing arrangements, customs and duties guarantees, and standby letters of credit for certain lease facilities. As of March 31, 2013 and December 31, 2012, the Company had $11.7 million and $12.6 million, respectively, in bank guarantees and standby letters of credit related to these financial guarantees.

Legal Proceedings

The Company is involved in disputes, litigation, and other legal actions, including, but not limited to, the matters described below. The Company is aggressively defending its current litigation matters, and while there can be no assurances and the outcome of these matters is currently not determinable, the Company currently believes that there are no existing claims or proceedings that are likely to have a material adverse effect on its financial position. There are many uncertainties associated with any litigation and these actions or other third-party claims against the Company may cause the Company to incur costly litigation and/or substantial settlement charges. In addition, the resolution of any intellectual property litigation may require the Company to make royalty payments, which could adversely affect gross margins in future periods. If any of those events were to occur, the Company's business, financial condition, results of operations, and cash flows could be adversely affected. The actual liability in any such matters may be materially different from the Company's estimates, if any, which could result in the need to adjust the liability and record additional expenses. Unless otherwise noted below, during the period presented, we have not: recorded any accrual for loss contingencies associated with such legal proceedings; determined that an unfavorable outcome is probable or reasonably possible; or determined that the amount or range of any possible loss is reasonably estimable.

2011 Federal Securities Class Action

On August 15, 2011, a purported securities class action lawsuit, captioned City of Royal Oak Retirement System v. Juniper Networks, Inc., et al., Case No. 11-cv-04003-LHK, was filed in the United States District Court for the Northern District of California naming the Company and certain of its officers and directors as defendants. The complaint alleges that the defendants made false and misleading statements regarding the Company's business and prospects. Plaintiffs seek an unspecified amount of monetary damages on behalf of the purported class. On January 9, 2012 the Court appointed City of Omaha Police and Fire Retirement System and City of Bristol Pension Fund as lead plaintiffs. Lead plaintiffs allege that defendants made false and misleading statements about the Company's business and future prospects, and failed to adequately disclose the impact of certain changes in accounting rules. Lead plaintiffs purport to assert claims for violations of Sections 10 (b), 20(a) and 20A of the Securities Exchange Act of 1934 and SEC Rule 10b-5 on behalf of those who purchased or otherwise acquired Juniper Networks' common stock between July 20, 2010 and July 26, 2011, inclusive. On March 14, 2012, Defendants filed motions to dismiss lead plaintiffs' amended complaint. On July 23, 2012, the Court issued an order dismissing the action and giving lead plaintiffs leave to file an amended complaint. Lead plaintiffs filed their second amended complaint on August 20, 2012. Defendants filed a motion to dismiss the second amended complaint on September 17, 2012, and lead plaintiffs filed their opposition on October 22, 2012. Defendants filed their reply brief on November 8, 2012. A hearing on the motion to dismiss is scheduled for May 16, 2013.

2011 California State Derivative Lawsuits

Between August 22 and September 9, 2011, four purported shareholder derivative actions were filed in the Superior Court of the State of California, County of Santa Clara, naming certain of the Company's officers and directors as defendants. The Company is named only as a nominal defendant in the actions. The actions were consolidated as In re Juniper Networks, Inc. Shareholder Litigation, Case No. 1-11-CV-207701 (Lead Case), by order dated September 12, 2011. The complaints are generally based upon the disclosures and alleged omissions challenged in the securities class action. The complaints purport to assert claims against the defendants for breach of fiduciary duties, unjust enrichment, abuse of control, gross mismanagement, and waste of corporate assets. The complaints seek, among other relief, damages in an unspecified amount, restitution, and attorneys' fees and costs. On March 8, 2012, the Company filed a motion to stay the action until resolution of the federal securities class action discussed above, and also filed a demurrer seeking to dismiss the action for the reason that plaintiffs lack standing. The plaintiffs filed oppositions to both motions on April 5, 2012. Defendants filed reply briefs on May 7, 2012. At a hearing on July 27, 2012, the Court ordered that the actions be stayed until such time as the federal court issues an order denying a motion to dismiss in the securities class action, City of Omaha Police and Fire Retirement System v. Juniper Networks, Inc. et al., Case No. CV-11-4003-LHK. The Court deferred deciding the demurrer pending the stay.

2011 Federal Derivative Lawsuit

On September 27, 2011 and December 28, 2011, two purported shareholder derivative actions, captioned Ratinova v. Johnson, et al., Case No. 11-cv-04792 and Lisa E. Coppola, ERA v. Johnson, et al., Case No. 11-cv-06667, respectively, were filed in the United States District Court for the Northern District of California naming certain of the Company's officers and directors as defendants. The Company is named only as a nominal defendant in the action. Like the state derivative actions, the federal derivative lawsuits are generally based upon the disclosures and alleged omissions challenged in the securities class action. The complaints purport to assert claims against the defendants for breach of fiduciary duties and unjust enrichment. The complaints seek, among other relief, damages in an unspecified amount, restitution, and attorneys' fees and costs. By order dated January 30, 2012, the Court consolidated the actions as In re Juniper Networks, Inc. Shareholder Derivative Litigation, Master File No. 11-cv-04792-LHK. On February 3, 2012, the parties filed a stipulation in which the parties requested that the Court stay the action until such time as the Court entered an order denying a motion to dismiss in the related federal securities class action described above. On February 6, 2012, the Court granted the parties' stipulation.

IRS Notices of Proposed Adjustments

The Company is currently under examination by the IRS for the 2007 through 2009 tax years.

In March 2013, the Company executed a closing agreement with the Appeals Division of the IRS related to its intercompany R&D cost sharing arrangement for the license of intangibles acquired in 2004, 2005 and 2006. The Company reached a final resolution with the IRS on all proposed adjustments for all tax years through 2006, which resulted in a settlement of approximately $20.9 million, including interest.