v3.26.1
Taxes on Earnings - Narrative (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Apr. 30, 2026
Apr. 30, 2025
Apr. 30, 2026
Apr. 30, 2025
Oct. 31, 2025
Income Tax Examination [Line Items]          
Provision (benefit) for taxes $ 75 $ 5 $ 56 $ 111  
Effective tax rate (as a percent) 10.70% (0.50%) 4.90% (35.60%)  
Effective income tax rate reconciliation, other reconciling items, amount $ 42 $ (94) $ (43) $ (111)  
Income tax rate reconciliation, valuation allowance, amount 29   (66)    
Effective income tax rate reconciliation, disposition of business, amount 24        
Effective income tax rate reconciliation, benefit, share-based payment arrangement, amount 23     31  
Effective income tax rate reconciliation, cost reduction program, amount   33   33  
Non domestic, amount       (33)  
Income tax benefit on restructuring charges, separation costs, transformation costs and acquisition and other related charges   33   14  
Net income tax benefits related to acquisition, disposition and other related charges   $ 16   16  
Disposition of asset       22  
Unrecognized tax benefits 875   875   $ 474
Unrecognized tax benefits that would affect effective tax rate if realized 413   413   326
Interest on income taxes expense     10    
Income ax penalties expense       $ 19  
Accrued income tax for interest and penalties 52   $ 52   $ 42
Income tax examination, description     The Company engages in continuous discussion and negotiation with tax authorities regarding tax matters in various jurisdictions. The Company is no longer subject to U.S. federal tax audits for years prior to 2020. The Internal Revenue Service (“IRS”) is conducting audits of the Company's fiscal 2020 through 2022 U.S. federal income tax returns. During the second quarter of fiscal 2026, the IRS issued notices of proposed adjustments (“NOPAs”) for fiscal 2020, 2021, and 2022 relating to the Company’s intercompany transfer pricing. During the second quarter of fiscal 2026, the Company submitted a formal settlement offer to the IRS to facilitate the closing of the audit and recorded increased reserves for unrecognized tax benefits of $318 million. The impact of the increase in reserves is almost entirely offset with a valuation allowance release, and the net impact to income tax expense for the three and six months ended April 30, 2026 was not material. It is reasonably possible that the IRS audit for fiscal 2020 through 2022 may be concluded in the next 12 months, and it is reasonably possible that existing unrecognized tax benefits related to these years may be reduced by an amount up to $369 million within the next 12 months; the majority of these unrecognized tax benefits are offset by adjustments to foreign tax credits that carry a full valuation allowance, which does not affect the Company’s effective tax rate.With respect to major state and foreign tax jurisdictions, the Company is no longer subject to tax authority examinations for years prior to 2005. As a result of the IRS audit for fiscal 2020 through 2022, the Company is recording additional state reserves of $57 million for the changes to federal taxable income. It is reasonably possible that certain foreign and state tax issues may be concluded in the next 12 months, including issues involving resolution of certain intercompany transactions and other matters. Juniper Networks is no longer subject to U.S. federal tax audits for years prior to 2022 and is not currently under examination by the IRS for other tax years.    
State, Local And Foreign Jurisdiction          
Income Tax Examination [Line Items]          
Increases in unrecognized tax benefits is reasonably possible     $ 318    
Income tax examination likelihood of conclusion period (in months)     12 months    
Decrease in unrecognized tax benefits is reasonably possible $ 369   $ 369    
State and Local Jurisdiction          
Income Tax Examination [Line Items]          
Increases in unrecognized tax benefits is reasonably possible     $ 57    
Income tax examination likelihood of conclusion period (in months)     12 months