Restructuring and Other Charges (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Restructuring Reserve [Line Items]
Restructuring and other charges	$ 1.4	$ 122.4
Restructuring reserve	9.4us-gaap_RestructuringReserve
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning of period	17.0us-gaap_RestructuringReserve
Restructuring charges	1.4us-gaap_RestructuringCharges
Cash Payments	(8.2)us-gaap_PaymentsForRestructuring
Non-cash Settlements and Other	(0.8)
Restructuring reserve, end of period	9.4us-gaap_RestructuringReserve
Cost of Revenues [Member]
Restructuring Reserve [Line Items]
Restructuring and other charges	0	8.4
Operating expense [Member]
Restructuring Reserve [Line Items]
Restructuring and other charges	1.4	114.0
Severance [Member]
Restructuring Reserve [Line Items]
Restructuring and other charges	1.5	28.3
Restructuring reserve	4.6
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning of period	9.4
Restructuring charges	1.5
Cash Payments	(5.9)
Non-cash Settlements and Other	(0.4)
Restructuring reserve, end of period	4.6
Severance [Member] \| Restructuring Plan 2014 [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges	1.5	28.0
Facilities [Member]
Restructuring Reserve [Line Items]
Restructuring and other charges	(0.1)	0.2
Restructuring reserve	4.6
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning of period	7.4
Restructuring charges	(0.1)
Cash Payments	(2.3)
Non-cash Settlements and Other	(0.4)
Restructuring reserve, end of period	4.6
Facilities [Member] \| Restructuring Plan 2014 [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges	0.1
Contract terminations [Member]
Restructuring Reserve [Line Items]
Restructuring and other charges	0	0.8
Restructuring reserve	0.2
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning of period	0.2
Restructuring charges	0
Cash Payments	0
Non-cash Settlements and Other	0
Restructuring reserve, end of period	0.2
Contract terminations [Member] \| Restructuring Plan 2014 [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges		0.8
Asset impairment and write-downs [Member]
Restructuring Reserve [Line Items]
Restructuring and other charges	0	93.1
Impairment charges related to licensed software [Member] \| Restructuring Plan 2014 [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges		84.7
Inventory Write-down [Member] \| Restructuring Plan 2014 [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges		8.4
Employee Severance and Contract Terminations [Member]
Restructuring Reserve [Line Items]
Restructuring reserve	4.8
Restructuring Reserve [Roll Forward]
Restructuring reserve, end of period	$ 4.8

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

Name:	us-gaap_PaymentsForRestructuring
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 420

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 420

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SAB TOPIC 5.P.4(b))

-URI http://asc.fasb.org/extlink&oid=27011515&loc=d3e140904-122747

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 420

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 5.P.3)

-URI http://asc.fasb.org/extlink&oid=27011515&loc=d3e140864-122747

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 5

-Section P

-Subsection 3, 4

+ Details

Name:	us-gaap_RestructuringCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_RestructuringCostAndReserveLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after cash payment, of expenses associated with exit or disposal activities pursuant to an authorized plan and expenses resulting from the write-down of assets. Excludes expenses related to a business combination, a discontinued operation or an asset retirement obligation.

+ References

+ Details

Name:	us-gaap_RestructuringCostsAndAssetImpairmentCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 420

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SAB TOPIC 5.P.4(b))

-URI http://asc.fasb.org/extlink&oid=27011515&loc=d3e140904-122747

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 5

-Section P

-Subsection 3, 4

+ Details

Name:	us-gaap_RestructuringReserve
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_RestructuringReserveRollForward
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of change in the restructuring reserve related to foreign currency translation adjustments and any other adjustments not separately disclosed or provided for elsewhere in the Taxonomy.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 420

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SAB TOPIC 5.P.4(b)(2))

-URI http://asc.fasb.org/extlink&oid=27011515&loc=d3e140904-122747

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 420

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (b)(2)

-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

+ Details

Name:	us-gaap_RestructuringReserveTranslationAndOtherAdjustment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_CostOfSalesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_OperatingExpenseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=jnpr_EmployeeSeveranceandContractTerminationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=jnpr_ImpairmentchargesrelatedtolicensedsoftwareMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=jnpr_InventoryWritedownMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=us-gaap_ContractTerminationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=us-gaap_EmployeeSeveranceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=us-gaap_FacilityClosingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=us-gaap_OtherRestructuringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: