v3.26.1
Taxes on Earnings - Narrative (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Jul. 31, 2026
Jul. 31, 2025
Jul. 31, 2026
Jul. 31, 2025
Oct. 31, 2025
Income Tax Examination [Line Items]          
Provision (benefit) for taxes $ 222 $ (17) $ 278 $ 94  
Effective tax rate (as a percent) 12.60% (6.50%) 9.60%    
Effective tax rate (as a percent)       (359.90%)  
Effective income tax rate reconciliation, other reconciling items, amount $ (84) $ 106 $ 41 $ 217  
Income tax rate reconciliation, valuation allowance, amount (118) 76 (118) 76  
Effective income tax rate reconciliation, benefit, share-based payment arrangement, amount 44   $ 66 30  
Income tax benefit on restructuring charges, separation costs, transformation costs and acquisition and other related charges   (21)   29  
Net income tax benefits related to acquisition, disposition and other related charges   $ 4   9  
Effective income tax rate reconciliation, cost reduction program, amount       33  
Non domestic, amount       33  
Net income tax benefits related to acquisition, disposition and other related charges       16  
Disposition of asset       22  
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 and fiscal 2024 through 2025 U.S. federal income tax returns. During the first 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 nine months ended July 31, 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 $366 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 recorded additional state unrecognized tax benefits of $51 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. The IRS is conducting an audit of Juniper’s 2024 U.S. federal income tax return.    
Unrecognized tax benefits 1,100   $ 1,100   $ 474
Unrecognized tax benefits that would affect effective tax rate if realized 522   522   326
Unrecognized tax benefits, increase resulting from acquisition     204    
Interest on income taxes expense     10    
Income ax penalties expense       $ 7  
Accrued income tax for interest and penalties 52   52   $ 42
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 $ 366   $ 366    
Income Tax Jurisdiction, Domestic State and Local          
Income Tax Examination [Line Items]          
Increases in unrecognized tax benefits is reasonably possible     $ 51    
Income tax examination likelihood of conclusion period (in months)     12 months