Juniper Networks (JNPR) 10-Q 8 May 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2014	2-May-14
Document and Entity Information [Abstract]	'	'
Entity Registrant Name	'JUNIPER NETWORKS INC	'
Entity Central Index Key	'0001043604	'
Document Type	'10-Q	'
Document Period End Date	31-Mar-14	'
Amendment Flag	'false	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Current Fiscal Year End Date	'--12-31	'
Entity Well-known Seasoned Issuer	'Yes	'
Entity Voluntary Filers	'No	'
Entity Current Reporting Status	'Yes	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	473,761,619

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (Unaudited) (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Net revenues:	'	'
Product	$876	$781.80
Service	294.1	277.4
Total net revenues	1,170.10	1,059.20
Cost of revenues:	'	'
Product	326.6	278.2
Service	123.4	110.2
Total cost of revenues	450	388.4
Gross margin	720.1	670.8
Operating expenses:	'	'
Research and development	264	262.2
Sales and marketing	273.4	256.1
General and administrative	74.9	58.5
Restructuring and other charges	114	7
Total operating expenses	726.3	583.8
Operating (loss) income	-6.2	87
Other income (expense), net	154.2	-10.1
Income before income taxes	148	76.9
Income tax provision (benefit)	37.4	-14.1
Net income	$110.60	$91
Net income per share:	'	'
Basic (in dollars per share)	$0.23	$0.18
Diluted (in dollars per share)	$0.22	$0.18
Shares used in computing net income per share:	'	'
Basic (in shares)	486.2	504.7
Diluted (in shares)	496.5	512.7

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Statement of Comprehensive Income [Abstract]	'	'
Net income	$110.60	$91
Available-for-sale securities:	'	'
Change in unrealized gains on available-for-sale securities, net of tax provision of ($22.1) for 2014	38.1	-0.2	[1]
Reclassification adjustment for realized net gains on available-for-sale securities included in net income, net of tax provision of $60.3 for 2014	-103.5	-0.4	[1]
Net change in unrealized gains on available-for-sale securities	-65.4	-0.6	[1]
Cash flow hedges:	'	'
Change in unrealized gains on cash flow hedges, net of tax provision of ($0.6) for 2014	2.1	-2.1	[1]
Reclassification adjustment for realized net gains on cash flow hedges included in net income, net of tax benefit of ($0.1) for 2014	-1.1	-1.4	[1]
Net change in unrealized gains on cash flow hedges, net of taxes	1	-3.5	[1]
Change in foreign currency translation adjustments	1.7	-5.8
Other comprehensive loss, net of tax	-62.7	-9.9
Comprehensive income	$47.90	$81.10
[1]	Taxes related to available-for-sale securities and cash flow hedges were not material for 2013.

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Comprehensive Income Parentheticals (Unaudited) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]	'
Tax provision on change in unrealized gains on available-for-sale securities	($22.10)
Tax provision on reclassification adjustment for realized net gains on available-for-sale securities included in net income	60.3
Tax provision on change in unrealized gains on cash flow hedges	-0.6
Tax benefit on reclassification adjustment for realized gains included in net income	($0.10)

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (Unaudited) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$2,579.40	$2,284
Short-term investments	378.1	561.9
Accounts receivable, net of allowances	597.9	578.3
Deferred tax assets, net	140.4	79.8
Prepaid expenses and other current assets	184	199.9
Total current assets	3,879.80	3,703.90
Property and equipment, net	905.7	882.3
Long-term investments	521.2	1,251.90
Restricted cash and investments	71.6	89.5
Purchased intangible assets, net	115.1	106.9
Goodwill	4,071.30	4,057.70
Other long-term assets	158.9	233.8
Total assets	9,723.60	10,326
Current liabilities:	'	'
Accounts payable	222.2	200.4
Accrued compensation	180.6	273.9
Deferred revenue	772.5	705.8
Other accrued liabilities	271	261.3
Total current liabilities	1,446.30	1,441.40
Long-term debt	1,348.90	999.3
Long-term deferred revenue	381.7	363.5
Long-term income taxes payable	121.7	114.4
Other long-term liabilities	115.5	105.2
Total liabilities	3,414.10	3,023.80
Commitments and contingencies (Note 16)	'	'
Stockholders' equity:	'	'
Convertible preferred stock, $0.00001 par value; 10.0 shares authorized; none issued and outstanding	0	0
Common stock, $0.00001 par value; 1,000.0 shares authorized; 473.4 shares and 495.2 shares issued and outstanding as of March 31, 2014 and December 31, 2013, respectively	0	0
Additional paid-in capital	9,255.40	9,868.90
Accumulated other comprehensive income	1.9	64.6
Accumulated deficit	-2,947.80	-2,631.30
Total stockholders' equity	6,309.50	7,302.20
Total liabilities and stockholders' equity	$9,723.60	$10,326

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets Parentheticals (Unaudited) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]	'	'
Convertible preferred stock - par value	$0.00	$0.00
Convertible preferred stock - shares authorized	10,000,000	10,000,000
Convertible preferred stock - issued	0	0
Convertible preferred stock - outstanding	0	0
Common stock - par value	$0.00	$0.00
Common stock - shares authorized	1,000,000,000	1,000,000,000
Common stock - issued	473,400,000	495,200,000
Common stock - outstanding	473,400,000	495,200,000

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:	'	'
Net income	$110.60	$91
Adjustments to reconcile net income to net cash provided by (used in) operating activities:	'	'
Share-based compensation expense	60.8	49.9
Depreciation, amortization, and accretion	48.1	51.8
Restructuring and other charges	122.4	7.7
Deferred income taxes	-44.5	15.7
Gain on investments, net	-166.2	-2.3
Excess tax benefits from share-based compensation	-6.7	-1.1
Loss on disposal of fixed assets	0.8	0.1
Changes in operating assets and liabilities, net of effects from acquisitions:	'	'
Accounts receivable, net	-15.7	-94.3
Prepaid expenses and other assets	35.5	-53.6
Accounts payable	19.2	9.1
Accrued compensation	-92	-75.2
Income taxes payable	21.2	-38.4
Other accrued liabilities	-50.3	-26.5
Deferred revenue	82.8	57.2
Net cash provided by (used in) operating activities	126	-8.9
Cash flows from investing activities:	'	'
Purchases of property and equipment	-57.3	-71.5
Purchases of available-for-sale investments	-327.1	-582.2
Proceeds from sales of available-for-sale investments	1,221.40	331.8
Proceeds from maturities of available-for-sale investments	79.3	54
Purchases of trading investments	-1.8	-1.5
Proceeds from sales of privately-held investments	2.5	1.6
Purchases of privately-held investments	-1.7	-7.3
Payments for business acquisitions, net of cash and cash equivalents acquired	-27.1	-10
Changes in restricted cash	25	0
Net cash provided by (used in) investing activities	913.2	-285.1
Cash flows from financing activities:	'	'
Proceeds from issuance of common stock	101.2	65
Purchases and retirement of common stock	-905.8	-132.5
Purchase of equity forward contract	-300	0
Issuance of long-term debt, net	346.5	0
Payment for capital lease obligation	-0.4	-1.4
Customer financing arrangements	8	-2.3
Excess tax benefits from share-based compensation	6.7	1.1
Net cash used in financing activities	-743.8	-70.1
Net increase (decrease) in cash and cash equivalents	295.4	-364.1
Cash and cash equivalents at beginning of period	2,284	2,407.80
Cash and cash equivalents at end of period	$2,579.40	$2,043.70

Basis_of_Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Basis of presentation	'
	Basis of Presentation
	Basis of Presentation
	The unaudited Condensed Consolidated Financial Statements of the Company have been prepared in accordance with United States ("U.S.") generally accepted accounting principles (“U.S. GAAP”) for interim financial information. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. The Condensed Consolidated Balance Sheet as of December 31, 2013, is derived from the audited Consolidated Financial Statements for the year ended December 31, 2013. In the opinion of management, all adjustments, including normal recurring accruals, considered necessary for a fair presentation have been included. The results of operations for the three months ended March 31, 2014, are not necessarily indicative of the results that may be expected for the year ending December 31, 2014, or any future period. The information included in this Quarterly Report on Form 10-Q ("Report") should be read in conjunction with “Management's Discussion and Analysis of Financial Condition and Results of Operations,” “Risk Factors,” “Quantitative and Qualitative Disclosures About Market Risk,” and the Consolidated Financial Statements and footnotes thereto included in the Company's Annual Report on Form 10-K for the year ended December 31, 2013. Certain amounts in the prior year Condensed Consolidated Financial Statements contained in this Report have been reclassified to conform to the current year presentation.
	The preparation of the financial statements and related disclosures in accordance with U.S. GAAP requires the Company to make judgments, assumptions, and estimates that affect the amounts reported in the Condensed Consolidated Financial Statements and the accompanying notes. Actual results could differ materially from those estimates under different assumptions or conditions.
	In the first quarter of 2014, the Company announced an integrated operating plan ("IOP") to refocus the Company's strategy, optimize its structure, and improve operational efficiencies. In connection with the IOP, the Company realigned its organization into a One-Juniper structure which includes consolidating the Company's R&D and go-to-market functions to reduce complexity, increase clarity of responsibilities, and improve efficiency. As a result of these changes, the consolidated business is considered to be one reportable segment. In fiscal 2013, the Company operated under two reportable segments: Platform Systems Division ("PSD") and Software Solutions Division ("SSD"). This change did not impact previously reported consolidated results of operation. See Note 13, Segments, for further discussion of the Company's segment reorganization.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Summary of significant accounting policies	'
	Summary of Significant Accounting Policies
	There have been no material changes to the Company's significant accounting policies as compared to the accounting policies described in Note 2, Significant Accounting Policies, in Notes to Consolidated Financial Statements in Item 8 of Part II of the Annual Report on Form 10-K for the year ended December 31, 2013.
	Recent Accounting Pronouncements
	In April 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2014-08, Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity ("ASU 2014-08") which raises the threshold for a disposal to qualify as a discontinued operation and requires new disclosures of both discontinued operations and certain other disposals that do not meet the definition of a discontinued operation. ASU 2014-08 is effective for annual periods beginning on or after December 15, 2014. Early adoption is permitted but only for disposals that have not been reported in financial statements previously issued. The Company is currently in the process of evaluating the impact of the adoption on its consolidated financial statements.
	In July 2013, the FASB issued ASU No. 2013-11, Income Taxes (Topic 740)—Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists (a consensus of the FASB Emerging Issues Task Force) ("ASU 2013-11") to provide explicit guidance on the financial statement presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. ASU 2013-11 became effective for the Company in the first quarter of 2014. The adoption did not result in a change to the tax provision and it did not have a significant impact to the presentation of long-term taxes payable or deferred tax assets.

Business_Combinations

Business Combinations	3 Months Ended
	Mar. 31, 2014
Business Combinations [Abstract]	'
Business Combinations	'
	Business Combinations
	On January 7, 2014, the Company acquired 100% of the equity securities of WANDL, Inc. ("WANDL"), for $28.7 million of cash and stock consideration. WANDL, a provider of software solutions for advanced planning, management, design and optimization of next-generation multi-layer networks will provide the Company with technology and experience in traffic engineering, multi-layer optimization and path computation, to help service provider customers optimize the performance and cost of their networks.
	The aggregate consideration of $28.7 million was allocated as follows: intangible assets of $17.8 million, recognized goodwill of $13.6 million, and net liabilities of $2.7 million. The goodwill recognized for the acquisition of WANDL was primarily attributable to expected synergies and is not deductible for U.S. federal income tax purposes.
	Additionally, under the terms of the purchase agreement, the Company assumed share-based awards for employees with a fair value of $34.9 million, which were granted in contemplation of future services and will be expensed as share-based compensation over the remaining service period.
	Intangible Assets Acquired
	The following table presents details of the Company's intangible assets acquired through the business combination completed during the three months ended March 31, 2014 (in millions, except years):
		Weighted	Amount
		Average
		Estimated
		Useful
		Life
		(In Years)
	Existing technology	7	$	10.7
	Customer relationships	7	6
	Trade name	4	0.6
	Backlog	1	0.2
	Non-compete agreements	2	0.3
	Total	7	$	17.8
	The Company's Condensed Consolidated Financial Statements include the operating results of this business combination from the date of acquisition. Pro forma results of operations for this acquisition have not been presented as the financial impact to the Company's consolidated results of operations is not material.
	The Company recognized $0.6 million and $0.1 million of acquisitions-related costs during the three months ended March 31, 2014 and March 31, 2013, respectively. These acquisition-related costs were expensed in the period incurred within general and administrative expense in the Company's Condensed Consolidated Statements of Operations.

Cash_Equivalents_and_Investmen

Cash Equivalents and Investments	3 Months Ended
	Mar. 31, 2014
Cash Equivalents and Investments [Abstract]	'
Cash Equivalents and Investments	'
	Cash Equivalents and Investments
	Investments in Available-for-Sale and Trading Securities
	The following tables summarize the Company's unrealized gains and losses and fair value of investments designated as available-for-sale and trading securities as of March 31, 2014 and December 31, 2013 (in millions):
		Amortized		Gross Unrealized			Gross Unrealized			Estimated Fair
		Cost		Gains			Losses			Value
	As of March 31, 2014
	Fixed income securities:
	Asset-backed securities	$	135.4	$	—		$	(0.1	)	$	135.3
	Certificates of deposit	12		—			—			12
	Commercial paper	1.2		—			—			1.2
	Corporate debt securities	411		1.3			(0.1		)	412.2
	Foreign government debt securities	5		—			—			5
	Government-sponsored enterprise obligations	88.3		—			—			88.3
	U.S. government securities	241.5		0.1			—			241.6
	Total fixed income securities	894.4		1.4			(0.2		)	895.6
	Money market funds	1,183.00		—			—			1,183.00
	Mutual funds	4		0.1			—			4.1
	Publicly-traded equity securities	7.2		—			(0.8		)	6.4
	Total available-for-sale securities	2,088.60		1.5			(1.0		)	2,089.10
	Trading securities in mutual funds(*)	16.1		—			—			16.1
	Total	$	2,104.70	$	1.5		$	(1.0	)	$	2,105.20
	Reported as:
	Cash equivalents	$	1,135.10	$	—		$	—		$	1,135.10
	Restricted investments	70.7		0.1			—			70.8
	Short-term investments	378.6		0.3			(0.8		)	378.1
	Long-term investments	520.3		1.1			(0.2		)	521.2
	Total	$	2,104.70	$	1.5		$	(1.0	)	$	2,105.20
	________________________________
	(*)	Balance includes the Company's non-qualified deferred compensation plan assets.
		Amortized		Gross Unrealized			Gross Unrealized			Estimated Fair
		Cost		Gains			Losses			Value
	As of December 31, 2013
	Fixed income securities:
	Asset-backed securities	$	249.9	$	0.1		$	(0.1	)	$	249.9
	Certificates of deposit	27.6		—			—			27.6
	Commercial paper	6.9		—			—			6.9
	Corporate debt securities	813.6		2			(0.3		)	815.3
	Foreign government debt securities	10.7		—			—			10.7
	Government-sponsored enterprise obligations	306.2		0.1			(0.1		)	306.2
	U.S. government securities	303.3		0.1			(0.1		)	303.3
	Total fixed income securities	1,718.20		2.3			(0.6		)	1,719.90
	Money market funds	1,043.70		—			—			1,043.70
	Mutual funds	3.9		0.1			—			4
	Publicly-traded equity securities	12		104.5			(1.9		)	114.6
	Total available-for-sale securities	2,777.80		106.9			(2.5		)	2,882.20
	Trading securities in mutual funds(*)	15.4		—			—			15.4
	Total	$	2,793.20	$	106.9		$	(2.5	)	$	2,897.60
	Reported as:
	Cash equivalents	$	996.2	$	—		$	—		$	996.2
	Restricted investments	87.5		0.1			—			87.6
	Short-term investments	459		104.9			(2.0		)	561.9
	Long-term investments	1,250.50		1.9			(0.5		)	1,251.90
	Total	$	2,793.20	$	106.9		$	(2.5	)	$	2,897.60
	________________________________
	(*)	Balance includes the Company's non-qualified deferred compensation plan assets.
	The following table presents the contractual maturities of the Company's total fixed income securities as of March 31, 2014 (in millions):
		Amortized		Gross Unrealized			Gross Unrealized			Estimated Fair
		Cost		Gains			Losses			Value
	Due within one year	$	374	$	0.3		$	—		$	374.3
	Due between one and five years	520.4		1.1			(0.2		)	521.3
	Total	$	894.4	$	1.4		$	(0.2	)	$	895.6
	The Company had 95 and 178 investments in an unrealized loss position as of March 31, 2014 and December 31, 2013, respectively. The gross unrealized losses related to these investments were primarily due to changes in market interest rates and stock prices. The Company reviews its investments to identify and evaluate investments that have an indication of possible impairment. The Company aggregates its investments by category and length of time the securities have been in a continuous unrealized loss position to facilitate its evaluation.
	For available-for-sale debt securities that have unrealized losses, the Company evaluates whether (i) it has the intention to sell any of these investments and (ii) whether it is more likely than not that it will be required to sell any of these investments before recovery of the entire amortized cost basis. As of March 31, 2014, the Company anticipates that it will recover the entire amortized cost basis of such available-for-sale debt securities and has determined that no other-than-temporary impairments associated with credit losses were required to be recognized during the three months ended March 31, 2014 and March 31, 2013.
For available-for-sale equity securities that have unrealized losses, the Company evaluates whether there is an indication of other-than-temporary impairments. This determination is based on several factors, including the financial condition and near-term prospects of the issuer and the Company's intent and ability to hold the publicly-traded equity securities for a period of time sufficient to allow for any anticipated recovery in market value. During the three months ended March 31, 2014, the Company determined that certain available-for-sale equity securities were other-than-temporarily impaired, resulting in an impairment charge of $1.6 million recorded within other income (expense), net, in the Condensed Consolidated Statements of Operations. There were no such charges during the three months ended March 31, 2013.
During the three months ended March 31, 2014, gross realized gains from available-for-sale securities were $165.5 million and gross realized losses were not material, excluding the impairment charge noted above. During the three months ended March 31, 2013, there were no material gross realized gains or losses from available-for-sale securities and there were no material gross realized gains or losses from trading securities during the three months ended March 31, 2014 and March 31, 2013.
The following tables present the Company's available-for-sale securities that were in an unrealized loss position as of March 31, 2014 and December 31, 2013 (in millions):
	Less than 12 Months					12 Months or Greater					Total
	Fair		Unrealized			Fair			Unrealized		Fair		Unrealized
	Value		Loss			Value			Loss		Value		Loss
As of March 31, 2014
Fixed income securities:
Asset-backed securities(1)	$	65.9	$	(0.1	)	$	6		$	—	$	71.9	$	(0.1	)
Corporate debt securities	54.1		(0.1		)	—			—		54.1		(0.1		)
Foreign government debt securities(1)	—		—			5			—		5		—
Government-sponsored enterprise obligations(2)	34.9		—			—			—		34.9		—
U.S. government securities(2)	6.9		—			—			—		6.9		—
Total fixed income securities	161.8		(0.2		)	11			—		172.8		(0.2		)
Publicly-traded equity securities	6.4		(0.8		)	—			—		6.4		(0.8		)
Total available-for-sale securities	$	168.2	$	(1.0	)	$	11		$	—	$	179.2	$	(1.0	)
________________________________
(1)	Balances greater than 12 months include investments that were in an immaterial unrealized loss position as of March 31, 2014.
(2)	Balances less than 12 months include investments that were in an immaterial unrealized loss position as of March 31, 2014.
	Less than 12 Months					12 Months or Greater					Total
	Fair		Unrealized			Fair			Unrealized		Fair		Unrealized
	Value		Loss			Value			Loss		Value		Loss
As of December 31, 2013
Fixed income securities:
Asset-backed securities(1)	$	153	$	(0.1	)	$	0.6		$	—	$	153.6	$	(0.1	)
Corporate debt securities(1)	156.1		(0.3		)	9.7			—		165.8		(0.3		)
Foreign government debt securities(2)	10		—			—			—		10		—
Government-sponsored enterprise obligations	123.1		(0.1		)	—			—		123.1		(0.1		)
U.S. government securities	119.7		(0.1		)	—			—		119.7		(0.1		)
Total fixed income securities	561.9		(0.6		)	10.3			—		572.2		(0.6		)
Publicly-traded equity securities	6.8		(1.9		)	—			—		6.8		(1.9		)
Total available-for-sale securities	$	568.7	$	(2.5	)	$	10.3		$	—	$	579	$	(2.5	)
________________________________
(1)	Balances greater than 12 months include investments that were in an immaterial unrealized loss position as of December 31, 2013.
(2)	Balances less than 12 months include investments that were in an immaterial unrealized loss position as of December 31, 2013.
Restricted Cash and Investments
The Company classifies cash and investments designated as available-for-sale securities as restricted cash and investments on its Condensed Consolidated Balance Sheets for: (i) amounts held in escrow accounts, as required in connection with certain acquisitions completed between 2005 and 2014; (ii) the India Gratuity Trust and Israel Retirement Trust, which cover statutory severance obligations in the event of termination of any of the Company's India and Israel employees, respectively; and (iii) the Directors and Officers indemnification trust ("D&O Trust").
Privately-Held Investments
As of March 31, 2014 and December 31, 2013, the carrying values of the Company’s privately-held investments of $58.7 million and $57.2 million, respectively, were included in other long-term assets in the Condensed Consolidated Balance Sheets.
The Company reviews its investments to identify and evaluate investments that have an indication of possible impairment. The Company adjusts the carrying value for its privately-held investments for any impairment if the fair value is less than the carrying value of the respective assets on an other-than-temporary basis. During the three months ended March 31, 2014 and March 31, 2013, the Company determined that no privately-held investments were other-than-temporarily impaired.

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	Fair Value Measurements
	Assets and Liabilities Measured at Fair Value on a Recurring Basis
	The following tables provide a summary of assets and liabilities measured at fair value on a recurring basis and as reported in the Condensed Consolidated Balance Sheets (in millions):
		Fair Value Measurements at March 31, 2014 Using:
		Quoted Prices in		Significant Other			Significant Other
		Active Markets For		Observable			Unobservable
		Identical Assets		Remaining Inputs			Remaining Inputs
		(Level 1)		(Level 2)			(Level 3)		Total
	Assets measured at fair value:
	Available-for-sale securities:
	Asset-backed securities	$	—	$	135.3		$	—	$	135.3
	Certificates of deposit	—		12			—		12
	Commercial paper	—		1.2			—		1.2
	Corporate debt securities	—		412.2			—		412.2
	Foreign government debt securities	—		5			—		5
	Government-sponsored enterprise obligations	—		88.3			—		88.3
	Money market funds(1)	1,183.00		—			—		1,183.00
	Mutual funds(2)	4.1		—			—		4.1
	Publicly-traded equity securities	6.4		—			—		6.4
	U.S. government securities	140.9		100.7			—		241.6
	Total available-for-sale securities	1,334.40		754.7			—		2,089.10
	Trading securities in mutual funds(3)	16.1		—			—		16.1
	Derivative assets:
	Foreign exchange contracts	—		3.7			—		3.7
	Total assets measured at fair value	$	1,350.50	$	758.4		$	—	$	2,108.90
	Liabilities measured at fair value:
	Derivative liabilities:
	Foreign exchange contracts	$	—	$	(0.1	)	$	—	$	(0.1	)
	Total liabilities measured at fair value	$	—	$	(0.1	)	$	—	$	(0.1	)
	Total assets measured at fair value, reported as:
	Cash equivalents	$	1,116.30	$	18.8		$	—	$	1,135.10
	Restricted investments	70.8		—			—		70.8
	Short-term investments	135.7		242.4			—		378.1
	Long-term investments	27.7		493.5			—		521.2
	Prepaid expenses and other current assets	—		3.7			—		3.7
	Total assets measured at fair value	$	1,350.50	$	758.4		$	—	$	2,108.90
	Total liabilities measured at fair value, reported as:
	Other accrued liabilities	$	—	$	(0.1	)	$	—	$	(0.1	)
	Total liabilities measured at fair value	$	—	$	(0.1	)	$	—	$	(0.1	)
	________________________________
	(1)	Balance includes $66.7 million of restricted investments measured at fair market value related to the Company's D&O Trust and acquisitions related escrows.
	(2)	Balance relates to restricted investments measured at fair market value related to the Company's India Gratuity Trust.
	(3)	Balance relates to investments measured at fair value related to the Company's non-qualified deferred compensation plan assets.
		Fair Value Measurements at December 31, 2013 Using:
		Quoted Prices in		Significant Other			Significant Other
		Active Markets For		Observable			Unobservable
		Identical Assets		Remaining Inputs			Remaining Inputs
		(Level 1)		(Level 2)			(Level 3)		Total
	Assets measured at fair value:
	Available-for-sale securities:
	Asset-backed securities	$	—	$	249.9		$	—	$	249.9
	Certificates of deposit	—		27.6			—		27.6
	Commercial paper	—		6.9			—		6.9
	Corporate debt securities	—		815.3			—		815.3
	Foreign government debt securities	—		10.7			—		10.7
	Government-sponsored enterprise obligations	—		306.2			—		306.2
	Money market funds(1)	1,043.70		—			—		1,043.70
	Mutual funds(2)	4		—			—		4
	Publicly-traded equity securities	114.6		—			—		114.6
	U.S. government securities	197.2		106.1			—		303.3
	Total available-for-sale securities	1,359.50		1,522.70			—		2,882.20
	Trading securities in mutual funds(3)	15.4		—			—		15.4
	Derivative assets:
Foreign exchange contracts	—		3			—		3
Total assets measured at fair value	$	1,374.90	$	1,525.70		$	—	$	2,900.60
Liabilities measured at fair value:
Derivative liabilities:
Foreign exchange contracts	$	—	$	(0.7	)	$	—	$	(0.7	)
Total liabilities measured at fair value	$	—	$	(0.7	)	$	—	$	(0.7	)
Total assets measured at fair value, reported as:
Cash equivalents	$	965.1	$	31.1		$	—	$	996.2
Restricted investments	87.6		—			—		87.6
Short-term investments	246.5		315.4			—		561.9
Long-term investments	75.7		1,176.20			—		1,251.90
Prepaid expenses and other current assets	—		3			—		3
Total assets measured at fair value	$	1,374.90	$	1,525.70		$	—	$	2,900.60
Total liabilities measured at fair value, reported as:
Other accrued liabilities	$	—	$	(0.7	)	$	—	$	(0.7	)
Total liabilities measured at fair value	$	—	$	(0.7	)	$	—	$	(0.7	)
________________________________
(1)	Balance includes $83.6 million of restricted investments measured at fair market value related to the Company's D&O Trust and acquisitions related escrows.
(2)	Balance relates to restricted investments measured at fair market value related to the Company's India Gratuity Trust.
(3)	Balance relates to investments measured at fair value related to the Company's non-qualified deferred compensation plan assets.
The Company's Level 2 available-for-sale fixed income securities are priced using quoted market prices for similar instruments or non-binding market prices that are corroborated by observable market data. The Company uses inputs such as actual trade data, benchmark yields, broker/dealer quotes, or alternative pricing sources with reasonable levels of price transparency which are obtained from quoted market prices, independent pricing vendors, or other sources, to determine the ultimate fair value of these assets. The Company's derivative instruments are classified as Level 2, as they are not actively traded and are valued using pricing models that use observable market inputs. The Company's policy is to recognize asset or liability transfers among Level 1, Level 2, and Level 3 at the beginning of the quarter in which a change in circumstances resulted in a transfer. During the three months ended March 31, 2014, the Company had no transfers between levels of the fair value hierarchy of its assets or liabilities measured at fair value.
Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis
Certain of the Company's assets, including intangible assets, goodwill, and privately-held investments, are measured at fair value on a nonrecurring basis if impairment is indicated.
Privately-held investments, which are normally carried at cost, are measured at fair value due to events and circumstances that the Company identified as significantly impacting the fair value of investments. The Company estimates the fair value of its privately-held investments using an analysis of the financial condition and near-term prospects of the investee, including recent financing activities and the investee's capital structure. Purchased intangible assets are measured at fair value primarily using discounted cash flow projections.
As of March 31, 2014, the Company had no assets measured at fair value on a nonrecurring basis. As of December 31, 2013, the Company had $2.0 million of privately-held investments measured at fair value on a nonrecurring basis and were classified as Level 3 assets due to the absence of quoted market prices and inherent lack of liquidity.
As of March 31, 2014 and December 31, 2013, the Company had no liabilities measured at fair value on a nonrecurring basis.
Assets and Liabilities Not Measured at Fair Value
The carrying amounts of the Company's accounts receivable, financing receivables, accounts payable, and other accrued liabilities approximate fair value due to their short maturities. As of March 31, 2014 and December 31, 2013, the estimated fair value of the Company's long-term debt in the Condensed Consolidated Balance Sheets was approximately $1,398.6 million and $1,023.5 million, respectively, based on observable market inputs (Level 2).

Derivative_Instruments

Derivative Instruments	3 Months Ended
	Mar. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivative Instruments	'
	Derivative Instruments
	The Company uses derivatives to partially offset its market exposure to fluctuations in certain foreign currencies and does not enter into derivatives for speculative or trading purposes.
	The notional amount of the Company's foreign currency derivatives are summarized as follows (in millions):
		As of
		March 31,		December 31,
		2014		2013
	Cash flow hedges	$	117.1	$	137.6
	Non-designated derivatives	153.8		144.4
	Total	$	270.9	$	282
	Cash Flow Hedges
	The Company uses foreign currency forward or option contracts to hedge certain forecasted foreign currency transactions relating to cost of services and operating expenses. The derivatives are intended to hedge the U.S. Dollar equivalent of the Company's planned cost of services and operating expenses denominated in foreign currencies. These derivatives are designated as cash flow hedges. Execution of these cash flow hedge derivatives typically occurs every month with maturities of one year or less. The effective portion of the derivative's gain or loss is initially reported as a component of accumulated other comprehensive income, and upon occurrence of the forecasted transaction, is subsequently reclassified into the cost of services or operating expense line item to which the hedged transaction relates. The Company records any ineffectiveness of the hedging instruments in other income (expense), net, in its Condensed Consolidated Statements of Operations. Cash flows from such hedges are classified as operating activities. All amounts within other comprehensive income are expected to be reclassified into earnings within the next twelve months.
	See Note 5, Fair Value Measurements, for the fair values of the Company's derivative instruments in the Condensed Consolidated Balance Sheets.
	During the three months ended March 31, 2014, the Company recognized a gain of $2.7 million in accumulated other comprehensive income for the effective portion of its derivative instruments and reclassified a gain of $1.0 million from other comprehensive loss to operating expense in the Condensed Consolidated Statements of Operations. During the three months ended March 31, 2013, the Company recognized a loss of $2.1 million in accumulated other comprehensive income for the effective portion of its derivative instruments and reclassified a gain of $1.4 million from other comprehensive loss to operating expense in the Condensed Consolidated Statements of Operations.
	The ineffective portion of the Company's derivative instruments recognized in its Condensed Consolidated Statements of Operations was not material during the three months ended March 31, 2014 and March 31, 2013.
	Non-Designated Derivatives
	The Company also uses foreign currency forward contracts to mitigate variability in gains and losses generated from the remeasurement of certain monetary assets and liabilities denominated in foreign currencies. These derivatives do not qualify for special hedge accounting treatment. These derivatives are carried at fair value with changes recorded in other income (expense), net, in the Condensed Consolidated Statements of Operations. Changes in the fair value of these derivatives are largely offset by remeasurement of the underlying assets and liabilities. Cash flows from such derivatives are classified as operating activities. The derivatives have maturities within two months.
	During the three months ended March 31, 2014 and March 31, 2013, the Company recognized net losses of $0.6 million and $0.7 million, respectively, on non-designated derivative instruments within other income (expense), net in its Condensed Consolidated Statements of Operations.
	Offsetting of Derivatives
	The Company presents its derivative assets and derivative liabilities on a gross basis in the Condensed Consolidated Balance Sheets. However, under agreements containing provisions on netting with certain counterparties of foreign exchange contracts, subject to applicable requirements, the Company is allowed to net-settle transactions on the same date in the same currency, with a single net amount payable by one party to the other. As of March 31, 2014 and December 31, 2013, the potential effect of rights of setoff associated with derivative instruments was not material. The Company is neither required to pledge nor entitled to receive cash collateral related to these derivative transactions.

Goodwill_and_Purchased_Intangi

Goodwill and Purchased Intangible Assets	3 Months Ended
	Mar. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]	'
Goodwill and Purchased Intangible Assets	'
	Goodwill and Purchased Intangible Assets
	Goodwill
	The following table presents goodwill activity during the three months ended March 31, 2014 (in millions):
	Balance as of December 31, 2013	$	4,057.70
	Additions due to business combinations	13.6
	Balance as of March 31, 2014	$	4,071.30
	The additions to goodwill were based on the purchase price allocation of the acquisition completed during the first quarter of 2014. There were no impairments to goodwill during the three months ended March 31, 2014 and March 31, 2013.
	Purchased Intangible Assets
	The Company’s purchased intangible assets were as follows (in millions):
		Gross		Accumulated			Impairments and			Net
				Amortization			Other Charges
	As of March 31, 2014
	Intangible assets with finite lives:
	Technologies and patents	$	592.1	$	(461.9	)	$	(30.5	)	$	99.7
	Customer contracts, support agreements, and	80.3		(63.7		)	(2.2		)	14.4
	related relationships
	Other	1.1		(0.1		)	—			1
	Total purchased intangible assets	$	673.5	$	(525.7	)	$	(32.7	)	$	115.1
	As of December 31, 2013
	Intangible assets with finite lives:
	Technologies and patents	$	581.4	$	(453.4	)	$	(30.5	)	$	97.5
	Customer contracts, support agreements, and	74.3		(62.7		)	(2.2		)	9.4
	related relationships
	Total purchased intangible assets	$	655.7	$	(516.1	)	$	(32.7	)	$	106.9
	The following table presents the amortization of intangible assets included in the Condensed Consolidated Statements of Operations (in millions):
		Three Months Ended March 31,
		2014		2013
	Cost of revenues	$	8.2	$	6.3
	Operating expenses:
	Sales and marketing	1		0.9
	General and administrative	0.3		0.3
	Total operating expenses	1.3		1.2
	Total	$	9.5	$	7.5
	There were no impairment charges related to purchased intangible assets during the three months ended March 31, 2014 and March 31, 2013.
	As of March 31, 2014, the estimated future amortization expense of purchased intangible assets with finite lives is as follows (in millions):
	Years Ending December 31,	Amount
	Remainder of 2014	$	29.3
	2015	35.3
	2016	21.1
	2017	13
	2018	6.1
	Thereafter	10.3
	Total	$	115.1

Other_Financial_Information

Other Financial Information	3 Months Ended
	Mar. 31, 2014
Other Financial Information [Abstract]	'
Other Financial Information	'
	Other Financial Information
	Inventories
	The Company purchases and holds inventory to provide adequate component supplies over the life of the underlying products. The majority of the Company's inventory is production components. Inventories are reported within prepaid expenses and other current assets and other long-term assets in the Condensed Consolidated Balance Sheets and consisted of the following (in millions):
		As of
		March 31,			December 31,
		2014			2013
	Production materials	$	53.5		$	51.3
	Finished goods	1.2			1.4
	Inventories	$	54.7		$	52.7
	In connection with the 2014 Restructuring Plan discussed in Note 9, Restructuring and Other Charges, the Company commenced a product rationalization initiative and accelerated the end-of-service life of certain products resulting in inventory charges of $8.4 million recorded within cost of revenues in the Condensed Consolidated Statement of Operations.
	Other Long-Term Assets
	Other long-term assets consisted of the following (in millions):
		As of
		March 31,			December 31,
		2014			2013
	Privately-held investments	$	58.7		$	57.2
	Licensed software	9.5			90.4
	Federal income tax receivable	20			20
	Financed customer receivable	20.9			19.9
	Inventory	14.9			15.2
	Prepaid costs, deposits, and other	34.9			31.1
	Other long-term assets	$	158.9		$	233.8
	In connection with the 2014 Restructuring Plan discussed in Note 9, Restructuring and Other Charges, the Company reviewed its product portfolio and determined to cease development of the application delivery controller software technology licensed in July 2012. As a result, the Company recognized a charge of $84.7 million recorded within operating expenses in the Condensed Consolidated Statement of Operations. There were no revenues associated with this technology.
	Warranties
	The Company accrues for warranty costs based on associated material, labor for customer support, and overhead at the time revenue is recognized. This accrual is reported as accrued warranty within current liabilities on the Condensed Consolidated Balance Sheets. Changes in the Company’s warranty reserve during the three months ended March 31, 2014 were as follows (in millions):
	Balance as of December 31, 2013	$	28
	Provisions made during the period, net	7.3
	Adjustments related to pre-existing warranties	—
	Actual costs incurred during the period	(6.9		)
	Balance as of March 31, 2014	$	28.4
	Deferred Revenue
	Details of the Company's deferred revenue, as reported on the Condensed Consolidated Balance Sheets, were as follows (in millions):
		As of
		March 31,			December 31,
		2014			2013
	Deferred product revenue:
	Undelivered product commitments and other product deferrals	$	186.3		$	184.9
	Distributor inventory and other sell-through items	93.8			118.7
	Deferred gross product revenue	280.1			303.6
	Deferred cost of product revenue	(48.9		)	(58.6		)
	Deferred product revenue, net	231.2			245
	Deferred service revenue	923			824.3
	Total	$	1,154.20		$	1,069.30
	Reported as:
	Current	$	772.5		$	705.8
	Long-term	381.7			363.5
	Total	$	1,154.20		$	1,069.30
	Deferred product revenue represents unrecognized revenue related to shipments to distributors that have not sold through to end-users, undelivered product commitments, and other shipments that have not met all revenue recognition criteria. Deferred product revenue is recorded net of the related costs of product revenue. Deferred service revenue represents billable amounts for service contracts, which include technical support, hardware and software maintenance, professional services, and training, for which services have not been rendered.
	Other Income (Expense), Net
	Other income (expense), net, consisted of the following (in millions):
		Three Months Ended March 31,
		2014			2013
	Interest income	$	2.1		$	2.1
	Interest expense	(15.4		)	(14.3		)
	Other	167.5			2.1
	Other income (expense), net	$	154.2		$	(10.1	)
	Interest income primarily includes interest earned on the Company’s cash, cash equivalents, and investments. Interest expense primarily includes interest, net of capitalized interest expense, from long-term debt and customer financing arrangements. Other typically consists of investment and foreign exchange gains and losses and other non-operational income and expense items.
	During the three months ended March 31, 2014, Other was primarily comprised of net realized gains of $164.0 million related to certain publicly-traded equity and privately-held investments. During the three months ended March 31, 2013, Other was primarily comprised of a $1.6 million gain related to the sale of a privately-held investment.

Restructuring_and_Other_Charge

Restructuring and Other Charges	3 Months Ended
	Mar. 31, 2014
Restructuring Charges [Abstract]	'
Restructuring and Other Charges	'
	Restructuring and Other Charges
	The following table presents restructuring and other charges included in cost of revenues and restructuring and other charges in the Condensed Consolidated Statements of Operations under the Company's restructuring plans (in millions):
		Three Months Ended March 31,
		2014		2013
	Severance	$	28.3	$	4.4
	Facilities	0.2		2.6
	Contract terminations	0.8		0.7
	Asset impairment and write-downs	93.1		—
	Total	$	122.4	$	7.7
	Reported as:
	Cost of revenues	$	8.4	$	0.7
	Restructuring and other charges	114		7
	Total	$	122.4	$	7.7
	Restructuring charges are based on the Company's restructuring plans that were committed to by management. Any changes in the estimates of executing the approved plans are reflected in the Company's results of operations.
	2014 Restructuring Plan
	In connection with IOP announced in the first quarter of 2014, the Company initiated a restructuring plan (the “2014 Restructuring Plan”) to refocus the Company's strategy, optimize its structure, and improve operational efficiencies. The 2014 Restructuring Plan consists of workforce reductions, facility consolidations or closures, asset write-downs, contract terminations and other charges.
	During the three months ended March 31, 2014, the Company recorded $28.0 million of severance costs, $84.7 million of impairment charges related to licensed software, and contract terminations of $0.8 million that were recorded to restructuring and other charges in the Condensed Consolidated Statement of Operations. The Company also recorded inventory write-downs related to the acceleration of the end-of-service life of certain products totaling $8.4 million to cost of revenues in the Condensed Consolidated Statement of Operations during the three months ended March 31, 2014. In connection with the 2014 Restructuring Plan, the Company expects to record aggregate future charges of approximately $60.0 million to $90.0 million allocated to the following restructuring activities: $9.0 million to $11.0 million for severance, $45.0 million to $55.0 million for facility consolidations or closures, $6.0 million to $12.0 million for asset write-downs, and up to $12.0 million for contract terminations and other charges.
	Other Plans
	Restructuring plans initiated by the Company in fiscal 2013, 2012, and 2011 have been substantially completed as of March 31, 2014 with minor adjustments recorded during the three months ended March 31, 2014 in connection with these plans. The Company expects to record aggregate future charges of approximately $2.5 million related to severance under these restructuring plans. The remaining restructuring liability under these plans related to facility charges are expected to be completed by March 2018.
	Restructuring liabilities are reported within other accrued liabilities and other long-term liabilities on the Condensed Consolidated Balance Sheets. The following table provides a summary of changes in the restructuring liability related to the Company's plans during the three months ended March 31, 2014 (in millions):
		December 31,		Charges		Cash			Non-cash			March 31,
		2013				Payments			Settlements and			2014
									Other
	Severance	$	5.6	$	28.3	$	(3.7	)	$	(0.6	)	$	29.6
	Facilities	5.1		0.2		(0.9		)	—			4.4
	Contract terminations and other	7.1		0.8		(7.0		)	(0.8		)	0.1
	Total	$	17.8	$	29.3	$	(11.6	)	$	(1.4	)	$	34.1

LongTerm_Debt_and_Financing

Long-Term Debt and Financing	3 Months Ended
	Mar. 31, 2014
Debt Instruments [Abstract]	'
Long-Term Debt and Financing	'
	Long-Term Debt and Financing
	Long-Term Debt
	The following table summarizes the Company's long-term debt (in millions, except percentages):
		As of March 31, 2014
		Amount			Effective Interest
					Rates
	Senior notes:
	3.10% fixed-rate notes, due 2016 ("2016 Notes")	$	300		3.25	%
	4.60% fixed-rate notes, due 2021 ("2021 Notes")	300			4.69	%
	4.50% fixed-rate notes, due 2024 ("2024 Notes")	350			4.63	%
	5.95% fixed-rate notes, due 2041 ("2041 Notes")	400			6.03	%
	Total senior notes	1,350.00
	Unaccreted discount	(1.1		)
	Total	$	1,348.90
	In February 2014, the Company issued $350.0 million aggregate principal amount of 4.50% senior notes due 2024. The 2024 Notes are senior unsecured obligations and rank equally with all of the Company's other existing and future senior unsecured indebtedness. Interest on the 2024 Notes is payable in cash semiannually. The Company may redeem the 2024 Notes, at any time in whole or from time to time in part, subject to a make-whole premium, and in the event of a change in control, the holders of the 2024 Notes may require the Company to repurchase for cash all or part of the 2024 Notes at a purchase price equal to 101% of the aggregate principal amount, plus accrued and unpaid interest, if any. The indenture that governs the 2024 Notes also contains various covenants, including limitations on the Company's ability to incur liens or enter into sale-leaseback transactions over certain dollar thresholds.
	The effective interest rates for the 2016 Notes, 2021 Notes, 2024 Notes, and 2041 Notes (collectively the “Notes”) include the interest on the Notes, accretion of the discount, and amortization of issuance costs. As of March 31, 2014, the Company was in compliance with all of its debt covenants.
	Customer Financing Arrangements
	The Company provides distribution partners access to extended financing arrangements for certain end-user customers that require longer payment terms than those typically provided by the Company through factoring accounts receivable to third-party financing providers ("financing providers"). The program does not and is not intended to affect the timing of the Company's revenue recognition. Under the financing arrangements, proceeds from the financing provider are due to the Company 30 days from the sale of the receivable. In these transactions with the financing provider, the Company surrenders control over the transferred assets. The factored accounts receivable are isolated from the Company and put beyond the reach of creditors, even in the event of bankruptcy. The Company does not maintain effective control over the transferred assets through obligations or rights to redeem, transfer, or repurchase the receivables after they have been transferred.
	Pursuant to the financing arrangements for the sale of receivables, the Company sold net receivables of $133.0 million and $181.0 million during the three months ended March 31, 2014 and March 31, 2013, respectively. The Company received cash proceeds from the financing provider of $192.3 million and $162.7 million during the three months ended March 31, 2014 and March 31, 2013, respectively. As of March 31, 2014 and December 31, 2013, the amounts owed by the financing provider were $127.9 million and $189.8 million, respectively, and were recorded in accounts receivable on the Condensed Consolidated Balance Sheets.
	The Company has provided guarantees for third-party financing arrangements extended to end-user customers, which have terms of up to four years. The Company is liable for the aggregate unpaid payments to the third-party financing company in the event of customer default. As of March 31, 2014, the Company has not been required to make any payments under these arrangements. Pursuant to these arrangements, the Company has guarantees for third-party financing arrangements of $21.9 million as of March 31, 2014.
	The portion of the receivable financed that has not been recognized as revenue is accounted for as a financing arrangement and is included in other accrued liabilities and other long-term liabilities in the Consolidated Balance Sheets. As of March 31, 2014 and December 31, 2013, the estimated cash received from the financing provider not recognized as revenue was $61.5 million and $62.3 million, respectively.

Equity

Equity	3 Months Ended
	Mar. 31, 2014
Stockholders' Equity Note [Abstract]	'
Equity	'
	Equity
	Stock Repurchase Activities
	In February 2014, the Company's Board of Directors (the "Board") approved a stock repurchase program that authorized the Company to repurchase up to $2.0 billion of its common stock through the end of the first quarter of 2015, including $1.2 billion to be used pursuant to an accelerated share repurchase program ("2014 Stock Repurchase Program"). The $2.0 billion authorization replaced the $1.0 billion authorization approved by the Board in July 2013 ("2013 Stock Repurchase Program").
	As part of the 2014 Stock Repurchase Program, the Company entered into two separate accelerated share repurchase agreements (collectively, the "ASR") with two financial institutions to repurchase $1.2 billion of the Company’s common stock. During the three months ended March 31, 2014, the Company made an up-front payment of $1.2 billion pursuant to the ASR and received and retired an initial 33.3 million shares ("Initial Shares") of the Company’s common stock for an aggregate price of $900.0 million based on the market value of the Company’s common stock on the date of the transaction and was accounted for as a reduction to stockholders' equity in the Condensed Consolidated Balance Sheets. The remaining $300.0 million was recorded as a forward contract within stockholders' equity in the Condensed Consolidated Balance Sheets.
	The total number of shares of the Company's common stock to be ultimately received under the ASR, will be based upon the average daily volume weighted average price of the Company's stock during the repurchase period, less an agreed upon discount. Final settlement of the transactions under the ASR is expected to be completed no sooner than May 27, 2014 or no later than August 27, 2014. If the Initial Shares are less than the total number of shares that will be ultimately received under the ASR, then the financial institution will be required to deliver additional shares of common stock to the Company at settlement. If however, the Initial Shares received are greater than the total number of shares that will be ultimately received, the Company has the option to either issue shares of common stock or make cash payments to the financial institutions.
	As of March 31, 2014, there was $800.0 million of authorized funds remaining under the 2014 Stock Repurchase Program.
	During the three months ended March 31, 2013, the Company repurchased and retired approximately 6.2 million shares of its common stock at an average price of $20.99 per share for an aggregate purchase price of $129.9 million under its 2013 Stock Repurchase Program.
	In addition to repurchases under the Company’s stock repurchase program, the Company also repurchases common stock from its employees in connection with the net issuance of shares to satisfy minimum tax withholding obligations for the vesting of certain stock awards. Repurchases associated with tax withholdings were not significant during the three months ended March 31, 2014 and March 31, 2013.
	Future share repurchases under the Company’s stock repurchase program will be subject to a review of the circumstances at that time and will be made from time to time in private transactions or open market purchases as permitted by securities laws and other legal requirements.
	Accumulated Other Comprehensive Income, Net of Tax
	The components of accumulated other comprehensive income, net of related taxes, during the three months ended March 31, 2014 were as follows (in millions):
		Unrealized			Unrealized			Foreign			Total
		Gains (Losses)			Gains (Losses)			Currency
		on Available-for-			on Cash Flow			Translation
		Sale Securities(1)			Hedges(2)			Adjustments
	Balance as of December 31, 2013	$	66.2		$	2.2		$	(3.8	)	$	64.6
	Other comprehensive gain before reclassifications	38.1			2.1			1.7			41.9
	Amount reclassified from accumulated other	(103.5		)	(1.1		)	—			(104.6		)
	comprehensive income
	Net other comprehensive loss	(65.4		)	1			1.7			(62.7		)
	Balance as of March 31, 2014	$	0.8		$	3.2		$	(2.1	)	$	1.9
	________________________________
	(1)	The reclassifications out of accumulated other comprehensive income during the three months ended March 31, 2014 for realized gains on available-for-sale securities of $103.5 million are included in other income (expense), net, in the Condensed Consolidated Statements of Operations.
	(2)	The reclassifications out of accumulated other comprehensive income during the three months ended March 31, 2014 for realized gains on cash flow hedges are included within cost of revenues of $0.2 million, sales and marketing of $1.1 million, and general and administrative of $0.1 million and for realized losses of $0.3 million within research and development for which the hedged transactions relate in the Condensed Consolidated Statements of Operations.

Employee_Benefit_Plans

Employee Benefit Plans	3 Months Ended
	Mar. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Employee Benefit Plans	'
	Employee Benefit Plans
	Equity Incentive Plans
	The Company’s equity incentive plans include the 2006 Equity Incentive Plan (the “2006 Plan”), the 2000 Nonstatutory Stock Option Plan (the “2000 Plan”), the Amended and Restated 1996 Stock Plan (the “1996 Plan”), various equity incentive plans assumed through acquisitions, and the 2008 Employee Stock Purchase Plan (the "ESPP"). Under these plans, the Company has granted (or in the case of acquired plans assumed) stock options, restricted stock units ("RSUs"), restricted stock awards ("RSAs"), and performance share awards ("PSAs").
	The 2006 Plan was adopted and approved by the Company’s stockholders in May 2006. To date, the Company's stockholders have approved a share reserve of 149.5 million shares of common stock plus the addition of any shares subject to options under the 2000 Plan and the 1996 Plan that were outstanding as of May 18, 2006, and that subsequently expire unexercised, up to a maximum of an additional 75.0 million shares. As of March 31, 2014, the 2006 Plan, the 2000 Plan, and the 1996 Plan, in the aggregate, had 33.9 million shares subject to currently outstanding equity awards. As of March 31, 2014, the 2006 Plan had 49.8 million shares available for future issuance and no shares are available for future issuance under either the 2000 Plan or the 1996 Plan.
	The ESPP was adopted in May 2008. To date, the Company's stockholders have approved a share reserve of 19.0 million shares of the Company's common stock for issuance under this plan. The ESPP permits eligible employees to acquire shares of the Company’s common stock at a 15% discount to the offering price (as determined in the ESPP) through periodic payroll deductions of up to 10% of base compensation, subject to individual purchase limits of 6,000 shares in any twelve-month period or $25,000 worth of stock, determined at the fair market value of the shares at the time the stock purchase option is granted, in one calendar year. As of March 31, 2014, approximately 14.4 million shares have been issued and 4.6 million shares remain available for future issuance under the ESPP.
	In connection with certain past acquisitions, the Company assumed stock options, RSUs, RSAs and PSAs under the assumed stock plans of the acquired companies and exchanged the assumed awards for the Company's stock options, RSUs, RSAs and PSAs, respectively. No new stock options, RSUs, RSAs and PSAs can be granted under these plans. As of March 31, 2014, stock options, RSUs, RSAs and PSAs representing approximately 5.7 million shares of common stock were outstanding under all awards assumed through the Company's acquisitions.
	Stock Option Activities
	The following table summarizes the Company’s stock option activity and related information as of and for the three months ended March 31, 2014 (in millions, except for per share amounts and years):
		Outstanding Options
		Number of Shares			Weighted Average			Weighted Average	Aggregate
					Exercise Price			Remaining	Intrinsic
					per Share			Contractual Term	Value
								(In Years)
	Balance as of December 31, 2013	23.1			$	25.15
	Canceled	(0.3	)		30.34
	Exercised	(3.7	)		20.24
	Expired	(0.6	)		28.76
	Balance as of March 31, 2014	18.5			$	25.92		2.2	$	52.9
	As of March 31, 2014:
	Vested and expected-to-vest options	18.2			$	26.04		2.1	$	50.1
	Exercisable options	16.7			$	26.48		1.8	$	36.3
	The aggregate intrinsic value represents the difference between the Company’s closing stock price on the last trading day of the period, which was $25.76 per share as of March 31, 2014, and the exercise price multiplied by the number of related options. The pre-tax intrinsic value of options exercised, representing the difference between the fair market value of the Company’s common stock on the date of exercise and the exercise price of each option, was $23.8 million for the three months ended March 31, 2014, respectively.
	Restricted Stock Unit, Restricted Stock Award, and Performance Share Award Activities
	The following table summarizes the Company’s RSU, RSA, and PSA activity and related information as of and for the three months ended March 31, 2014 (in millions, except per share amounts and years):
		Outstanding RSUs, RSAs, and PSAs
		Number of Shares			Weighted Average			Weighted Average	Aggregate
					Grant-Date Fair			Remaining	Intrinsic
					Value per Share			Contractual Term	Value
								(In Years)
	Balance as of December 31, 2013	25.4			$	23.44
	RSUs granted (1)(4)	1.9			22.14
	RSUs assumed (2)	0.4			22.66
	RSAs assumed (2)	0.9			22.66
	PSAs granted (3)(4)	0.8			25.22
	PSAs assumed (2)	0.2			22.66
	RSUs vested	(4.6	)		24.05
	RSAs vested	(0.3	)		19.59
	PSAs vested	(1.0	)		38.1
	RSUs canceled	(0.5	)		21.55
	PSAs canceled	(2.1	)		33.85
	Balance as of March 31, 2014	21.1			$	21.57		1.4	$	543.3
	________________________________
	(1)	Includes service-based and market-based RSUs granted under the 2006 Plan according to its terms.
	(2)	RSUs, RSAs, and PSAs assumed in connection with the acquisition of WANDL.
	(3)	The number of shares subject to PSAs granted represents the aggregate maximum number of shares that may be issued pursuant to the award over its full term. The aggregate number of shares subject to these PSAs that would be issued if performance goals determined by the Compensation Committee are achieved at target is 0.4 million shares. Depending on achievement of such performance goals, the range of shares that could be issued under these awards is 0 to 0.8 million shares.
	(4)	On February 20, 2014, the Company announced its intention to initiate a quarterly cash dividend of $0.10 per share of common stock in the third quarter of 2014. As a result of the Company's announcement, the grant date fair value of RSUs and PSAs granted after the announcement date were reduced by the present value of the dividends expected to be paid on the underlying shares of common stock during the requisite and derived service period as these awards are not entitled to receive dividends until vested.
	Employee Stock Purchase Plan
	The Company's ESPP is implemented in a series of offering periods, each six months in duration, or a shorter period as determined by the Board. Employees purchased 1.5 million and 1.9 million shares of common stock through the ESPP at an average exercise price of $18.67 and $15.05 per share for the three months ended March 31, 2014 and March 31, 2013, respectively.
	Valuation Assumptions
	The weighted-average assumptions used and the resulting estimates of fair value for ESPP and market-based RSUs were as follows:
		Three Months Ended March 31,
		2014		2013
	ESPP (1):
	Volatility	33%		36%
	Risk-free interest rate	0.10%		0.10%
	Expected life (years)	0.5		0.5
	Dividend yield	—		—
	Weighted-average fair value per share	$6.37		$5.63
	Market-based RSUs (2):
	Volatility	36%		—
	Risk-free interest rate	1.60%		—
	Dividend yield	0% - 1.5%		—
	Weighted-average fair value per share	$18.28		—
________________________________
(1)	The Black-Scholes-Merton option-pricing model is utilized to estimate the fair value of ESPP.
(2)	The fair value of market-based RSUs utilizes a Monte Carlo valuation methodology. The Company amortizes the fair value of these awards over the derived service period adjusted for estimated forfeitures for each separately vesting tranche of the award. Provided that the derived service is rendered, the total fair value of the market-based RSUs at the date of grant is recognized as compensation expense even if the market condition is not achieved. However, the number of shares that ultimately vest can vary significantly with the performance of the specified market criteria.
Share-Based Compensation Expense
Share-based compensation expense associated with stock options, RSUs, RSAs, PSAs, and ESPP was recorded in the following cost and expense categories in the Condensed Consolidated Statements of Operations (in millions):
	Three Months Ended March 31,
	2014				2013
Cost of revenues - Product	$	1.3			$	0.9
Cost of revenues - Service	4				4.6
Research and development	32.1				23.6
Sales and marketing	14.6				14.5
General and administrative	8.8				6.3
Total	$	60.8			$	49.9
The following table summarizes share-based compensation expense by award type (in millions):
	Three Months Ended March 31,
	2014				2013
Stock options	$	5.1			$	9.5
RSUs, RSAs, and PSAs	51.8				37
ESPP	3.9				3.4
Total	$	60.8			$	49.9
The following table presents unrecognized compensation cost, adjusted for estimated forfeitures, recognized over a weighted-average period related to unvested stock options, RSUs, RSAs, and PSAs as of March 31, 2014 (in millions, except years):
	Unrecognized				Weighted Average
	Compensation Cost				Period
					(In Years)
Stock options	$	25.9			1.7
RSUs, RSAs, and PSAs	$	293.1			2

Segments

Segments	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Segments	'
	Segments
	In connection with the IOP, the Company realigned its organization into a One-Juniper structure which includes consolidating the Company's R&D and go-to-market functions to reduce complexity, increase clarity of responsibilities, and improve efficiency. As a result of these changes, the consolidated business is considered to be one reportable segment and operating segment, consistent with how the Company’s chief operating decision maker (“CODM”) views the business, allocates resources, and assesses the performance of the Company.
	The Company continues to sell its high-performance network products and service offerings across routing, switching, and security to service provider and enterprise markets.
	The following table presents net revenues by product and service (in millions):
		Three Months Ended March 31,
		2014		2013
	Routing	$	549.8	$	513.6
	Switching	192		131.5
	Security	134.2		136.7
	Total product	876		781.8
	Total service	294.1		277.4
	Total	$	1,170.10	$	1,059.20
	The Company attributes revenues to geographic region based on the customer’s ship-to location. The following table presents net revenues by geographic region (in millions):
		Three Months Ended March 31,
		2014		2013
	Americas:
	United States	$	623.7	$	547
	Other	57.8		45.1
	Total Americas	681.5		592.1
	Europe, Middle East, and Africa	295.7		290.6
	Asia Pacific	192.9		176.5
	Total	$	1,170.10	$	1,059.20
	No customer accounted for greater than 10% of the Company's net revenues during the three months ended March 31, 2014. During the three months ended March 31, 2013, AT&T and Verizon Communications, Inc. ("Verizon") accounted for 10.2% and 10.1% of net revenues, respectively.
	The following table presents geographic information for property and equipment, net (in millions):
		As of
		March 31,		December 31,
		2014		2013
	United States	$	823	$	801.3
	International	82.7		81
	Property and equipment, net	$	905.7	$	882.3
	The Company tracks assets by physical location. The majority of the Company’s assets, excluding cash and cash equivalents and investments, as of March 31, 2014 and December 31, 2013, were attributable to U.S. operations.

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	The Company's effective tax rate for the three months ended March 31, 2014 of 25.3%, was lower than the federal statutory rate of 35% primarily due to the benefit from the Section 199 deduction for U.S. production activities, earnings in foreign jurisdictions, which are subject to lower tax rates, and the impact of the discrete items noted below. The effective rate for the period does not reflect the benefit of the federal R&D credit, which expired on December 31, 2013.
	The effective tax rate for the three months ended March 31, 2013 of (18.3)%, differs from the federal statutory rate of 35% primarily due to the benefit from earnings in foreign jurisdiction, which are subject to lower tax rates, the impact of the recognition of tax benefits related to a tax settlement with the Internal Revenue Service (“IRS”) and the reinstatement of the U.S. federal research and development (“R&D”) tax credit on January 2, 2013.
	The effective tax rates for the three months ended March 31, 2014 and March 31, 2013 include the tax expense (benefit) of the following discrete items (in millions):
		Three Months Ended March 31,
		2014			2013
	Tax on gain of equity investments, net of valuation allowance release of $24.7	$	35.6		$	—
	Benefit from restructuring costs	$	(30.8	)	$	—
	Tax settlement with Internal Revenue Service (“IRS”)	$	—		$	(27.8	)
	Reinstatement of the U.S. federal R&D tax credit	$	—		$	(15.2	)
	As of March 31, 2014, the total amount of gross unrecognized tax benefits was $142.9 million, of which $131.9 million, if recognized, would affect the Company's effective tax rate.
	The Company engages in continuous discussions and negotiations with tax authorities regarding tax matters in various jurisdictions. There is a greater than remote likelihood that the balance of the gross unrecognized tax benefits will decrease by approximately $2.5 million within the next twelve months due to lapses of applicable statutes of limitation and the completion of tax review cycles in various tax jurisdictions.
	The Company is currently under examination by the IRS for the 2007 through 2009 tax years. The Company is also subject to separate ongoing examinations by the India tax authorities for the 2004 tax year, 2004 through 2008 tax years, and the 2008 through 2010 tax years. The Company is not aware of any other examinations by tax authorities in any other major jurisdictions in which it files income tax returns as of March 31, 2014.
	In 2008, the Company received a proposed adjustment from the India tax authorities related to the 2004 tax year. In 2009, the India tax authorities commenced a separate investigation of our 2004 through 2008 tax returns and are disputing the Company's determination of taxable income due to the cost basis of certain fixed assets. The Company accrued $4.6 million in penalties and interest in 2009 related to this matter. The Company understands that in accordance with the administrative and judicial process
	in India, the Company may be required to make payments that are substantially higher than the amount accrued in order to ultimately settle this issue. The Company strongly believes that any assessment it may receive in excess of the amount accrued would be inconsistent with applicable India tax laws and intends to defend this position vigorously.
	The Company is pursuing all available administrative remedies relative to these matters. The Company believes that it has adequately provided for any reasonably foreseeable outcomes related to these proposed adjustments and the ultimate resolution of these matters is unlikely to have a material effect on its consolidated financial condition or results of operations; however there is still a possibility that an adverse outcome of these matters could have a material effect on its consolidated financial condition and results of operations.

Net_Income_per_Share

Net Income per Share	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Net Income Per Share	'
	Net Income Per Share
	The Company computed basic and diluted net income per share as follows (in millions, except per share amounts):
		Three Months Ended March 31,
		2014		2013
	Numerator:
	Net income	$	110.6	$	91
	Denominator:
	Weighted-average shares used to compute	486.2		504.7
	basic net income per share
	Dilutive effect of employee stock awards	10.3		8
	Weighted-average shares used to compute	496.5		512.7
	diluted net income per share
	Net income per share:
	Basic	$	0.23	$	0.18
	Diluted	$	0.22	$	0.18
	Anti-dilutive:
	Potential anti-dilutive shares	25.4		24.7
	Basic net income per share is computed using net income available to common stockholders and the weighted-average number of common shares outstanding for the period. Diluted net income per share is computed using net income available to common stockholders and the weighted-average number of common shares outstanding plus potentially dilutive common shares outstanding during the period. Dilutive potential common shares consist of common shares issuable upon exercise of stock options, issuances of ESPP, and vesting of RSUs, RSAs, and PSAs. The Company includes the common shares underlying PSAs in the calculation of diluted net income per share when they become contingently issuable and excludes such shares when they are not contingently issuable. Potentially dilutive common shares were excluded from the computation of diluted net income per share because their effect would be anti-dilutive.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	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 $221.3 million as of March 31, 2014. Rent expense was $13.0 million and $13.7 million for the three months ended March 31, 2014 and March 31, 2013, respectively.
	Purchase Commitments with Contract Manufacturers and Suppliers
	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 $489.7 million as of March 31, 2014.
	The Company establishes a liability in connection with purchase commitments related to quantities in excess of its demand forecasts or obsolete materials charges for components purchased by the contract manufacturers based on the Company’s demand forecast or customer orders. As of March 31, 2014, the Company accrued $20.5 million based on its estimate of such charges.
	Long-Term Debt and Interest Payment on Long-Term Debt
	As of March 31, 2014, the Company held long-term debt consisting of senior notes with a carrying value of $1,348.9 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%, $350.0 million will mature in 2024 and bears interest at a fixed rate of 4.50%, 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, 2014, other contractual obligations primarily consisted of $71.6 million in indemnity-related and service related escrows, as required in connection with certain asset purchases and acquisitions completed between 2005 and 2014, campus build-out obligations of $13.9 million, and $7.8 million of agreements that are firm, non-cancelable and specify terms, including: fixed or minimum quantities to be purchased; fixed, minimum or variable price provisions; and the approximate timing of payment.
	Tax Liabilities
	As of March 31, 2014, the Company had $121.7 million included in long-term income 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, custom and duty guarantees, and standby letters of credit for certain lease facilities. As of March 31, 2014 and December 31, 2013, the Company had $28.7 million and $40.1 million, respectively, in financing arrangements, bank guarantees, and standby letters of credit related to these financial guarantees, of which $21.9 million in financing guarantees was recorded in other accrued liabilities and other long-term liabilities in the Condensed Consolidated Balance Sheets as of March 31, 2014. See Note 10, Long-Term Debt and Financing, for further discussion of the Company's third-party customer financing arrangements that contain guarantee provisions.
	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. 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.
	2013 Federal Securities Class Action
	On August 12, 2013, a purported securities class action lawsuit, captioned Warren Avery v. Juniper Networks, Inc., et al., Case No. 13-cv-3733-WHO, 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 alleged that the defendants made false and misleading statements regarding the Company's revenues, business practices, and internal controls. The complaint purported to assert claims for violations of Sections 10 (b) and 20(a) of the Securities Exchange Act of 1934 and SEC Rule 10b-5 on behalf of those who purchased Juniper Networks' securities between April 24, 2012 and August 8, 2013, inclusive. Plaintiff sought an unspecified amount of monetary damages on behalf of the purported class. On November 12, 2013, the court issued an order appointing Warren Avery as lead plaintiff. On January 9, 2014, lead plaintiff filed a notice of voluntary dismissal of the action without prejudice. On January, 23, 2014, the court entered an order of dismissal without prejudice.
	2013 Shareholder Derivative Lawsuit
	On August 28, 2013, a purported shareholder derivative action captioned Washtenaw County Employees’ Retirement System v. Kriens, et al., Case No. 1-13-CV-252083, was 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. On October 17, 2013, the action was removed to the United States District Court for the Northern District of California, and is now Case No. 13-cv-04829-WHO. The Company is named only as a nominal defendant in the action. The complaint alleges that the defendants failed to implement adequate internal controls and compliance programs to prevent violations of the Foreign Corrupt Practices Act. The complaint purports to assert claims against the defendants for breach of fiduciary duties, abuse of control, and waste of corporate assets. The complaint seeks, among other relief, damages in an unspecified amount, restitution, and attorneys' fees and costs. On January 22, 2014, the Company filed a motion to dismiss the action. On March 6, 2014, plaintiff filed a stipulation of voluntary dismissal, and on March 12, 2014, the Court entered an order of dismissal without prejudice.
	Investigations
	The U.S. Securities and Exchange Commission and the U.S. Department of Justice are conducting investigations into possible violations by the Company of the U.S. Foreign Corrupt Practices Act. The Company is cooperating with these agencies regarding these matters. The Company is unable to predict the duration, scope or outcome of these investigations.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Recent accounting pronouncements	'
	Recent Accounting Pronouncements
	In April 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2014-08, Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity ("ASU 2014-08") which raises the threshold for a disposal to qualify as a discontinued operation and requires new disclosures of both discontinued operations and certain other disposals that do not meet the definition of a discontinued operation. ASU 2014-08 is effective for annual periods beginning on or after December 15, 2014. Early adoption is permitted but only for disposals that have not been reported in financial statements previously issued. The Company is currently in the process of evaluating the impact of the adoption on its consolidated financial statements.
	In July 2013, the FASB issued ASU No. 2013-11, Income Taxes (Topic 740)—Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists (a consensus of the FASB Emerging Issues Task Force) ("ASU 2013-11") to provide explicit guidance on the financial statement presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. ASU 2013-11 became effective for the Company in the first quarter of 2014. The adoption did not result in a change to the tax provision and it did not have a significant impact to the presentation of long-term taxes payable or deferred tax assets.

Business_Combination_Tables

Business Combination (Tables)	3 Months Ended
	Mar. 31, 2014
Business Combinations [Abstract]	'
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block]	'
	The following table presents details of the Company's intangible assets acquired through the business combination completed during the three months ended March 31, 2014 (in millions, except years):
		Weighted	Amount
		Average
		Estimated
		Useful
		Life
		(In Years)
	Existing technology	7	$	10.7
	Customer relationships	7	6
	Trade name	4	0.6
	Backlog	1	0.2
	Non-compete agreements	2	0.3
	Total	7	$	17.8

Cash_Equivalents_and_Investmen1

Cash Equivalents and Investments (Tables)	3 Months Ended
	Mar. 31, 2014
Cash Equivalents and Investments [Abstract]	'
Unrealized gains and losses and fair value of available-for-sale and trading securities	'
	The following tables summarize the Company's unrealized gains and losses and fair value of investments designated as available-for-sale and trading securities as of March 31, 2014 and December 31, 2013 (in millions):
		Amortized		Gross Unrealized			Gross Unrealized			Estimated Fair
		Cost		Gains			Losses			Value
	As of March 31, 2014
	Fixed income securities:
	Asset-backed securities	$	135.4	$	—		$	(0.1	)	$	135.3
	Certificates of deposit	12		—			—			12
	Commercial paper	1.2		—			—			1.2
	Corporate debt securities	411		1.3			(0.1		)	412.2
	Foreign government debt securities	5		—			—			5
	Government-sponsored enterprise obligations	88.3		—			—			88.3
	U.S. government securities	241.5		0.1			—			241.6
	Total fixed income securities	894.4		1.4			(0.2		)	895.6
	Money market funds	1,183.00		—			—			1,183.00
	Mutual funds	4		0.1			—			4.1
	Publicly-traded equity securities	7.2		—			(0.8		)	6.4
	Total available-for-sale securities	2,088.60		1.5			(1.0		)	2,089.10
	Trading securities in mutual funds(*)	16.1		—			—			16.1
	Total	$	2,104.70	$	1.5		$	(1.0	)	$	2,105.20
	Reported as:
	Cash equivalents	$	1,135.10	$	—		$	—		$	1,135.10
	Restricted investments	70.7		0.1			—			70.8
	Short-term investments	378.6		0.3			(0.8		)	378.1
	Long-term investments	520.3		1.1			(0.2		)	521.2
	Total	$	2,104.70	$	1.5		$	(1.0	)	$	2,105.20
	________________________________
	(*)	Balance includes the Company's non-qualified deferred compensation plan assets.
		Amortized		Gross Unrealized			Gross Unrealized			Estimated Fair
		Cost		Gains			Losses			Value
	As of December 31, 2013
	Fixed income securities:
	Asset-backed securities	$	249.9	$	0.1		$	(0.1	)	$	249.9
	Certificates of deposit	27.6		—			—			27.6
	Commercial paper	6.9		—			—			6.9
	Corporate debt securities	813.6		2			(0.3		)	815.3
	Foreign government debt securities	10.7		—			—			10.7
	Government-sponsored enterprise obligations	306.2		0.1			(0.1		)	306.2
	U.S. government securities	303.3		0.1			(0.1		)	303.3
	Total fixed income securities	1,718.20		2.3			(0.6		)	1,719.90
	Money market funds	1,043.70		—			—			1,043.70
	Mutual funds	3.9		0.1			—			4
	Publicly-traded equity securities	12		104.5			(1.9		)	114.6
	Total available-for-sale securities	2,777.80		106.9			(2.5		)	2,882.20
	Trading securities in mutual funds(*)	15.4		—			—			15.4
	Total	$	2,793.20	$	106.9		$	(2.5	)	$	2,897.60
	Reported as:
	Cash equivalents	$	996.2	$	—		$	—		$	996.2
	Restricted investments	87.5		0.1			—			87.6
	Short-term investments	459		104.9			(2.0		)	561.9
	Long-term investments	1,250.50		1.9			(0.5		)	1,251.90
	Total	$	2,793.20	$	106.9		$	(2.5	)	$	2,897.60
	________________________________
	(*)	Balance includes the Company's non-qualified deferred compensation plan assets.
Maturities of fixed income securities	'
	The following table presents the contractual maturities of the Company's total fixed income securities as of March 31, 2014 (in millions):
		Amortized		Gross Unrealized			Gross Unrealized			Estimated Fair
		Cost		Gains			Losses			Value
	Due within one year	$	374	$	0.3		$	—		$	374.3
	Due between one and five years	520.4		1.1			(0.2		)	521.3
	Total	$	894.4	$	1.4		$	(0.2	)	$	895.6
Available-for-sale securities in unrealized loss position	'
	The following tables present the Company's available-for-sale securities that were in an unrealized loss position as of March 31, 2014 and December 31, 2013 (in millions):
		Less than 12 Months					12 Months or Greater					Total
		Fair		Unrealized			Fair			Unrealized		Fair		Unrealized
		Value		Loss			Value			Loss		Value		Loss
	As of March 31, 2014
	Fixed income securities:
	Asset-backed securities(1)	$	65.9	$	(0.1	)	$	6		$	—	$	71.9	$	(0.1	)
	Corporate debt securities	54.1		(0.1		)	—			—		54.1		(0.1		)
	Foreign government debt securities(1)	—		—			5			—		5		—
	Government-sponsored enterprise obligations(2)	34.9		—			—			—		34.9		—
	U.S. government securities(2)	6.9		—			—			—		6.9		—
	Total fixed income securities	161.8		(0.2		)	11			—		172.8		(0.2		)
	Publicly-traded equity securities	6.4		(0.8		)	—			—		6.4		(0.8		)
	Total available-for-sale securities	$	168.2	$	(1.0	)	$	11		$	—	$	179.2	$	(1.0	)
	________________________________
	(1)	Balances greater than 12 months include investments that were in an immaterial unrealized loss position as of March 31, 2014.
	(2)	Balances less than 12 months include investments that were in an immaterial unrealized loss position as of March 31, 2014.
		Less than 12 Months					12 Months or Greater					Total
		Fair		Unrealized			Fair			Unrealized		Fair		Unrealized
		Value		Loss			Value			Loss		Value		Loss
	As of December 31, 2013
	Fixed income securities:
	Asset-backed securities(1)	$	153	$	(0.1	)	$	0.6		$	—	$	153.6	$	(0.1	)
	Corporate debt securities(1)	156.1		(0.3		)	9.7			—		165.8		(0.3		)
	Foreign government debt securities(2)	10		—			—			—		10		—
	Government-sponsored enterprise obligations	123.1		(0.1		)	—			—		123.1		(0.1		)
	U.S. government securities	119.7		(0.1		)	—			—		119.7		(0.1		)
	Total fixed income securities	561.9		(0.6		)	10.3			—		572.2		(0.6		)
	Publicly-traded equity securities	6.8		(1.9		)	—			—		6.8		(1.9		)
	Total available-for-sale securities	$	568.7	$	(2.5	)	$	10.3		$	—	$	579	$	(2.5	)
	________________________________
	(1)	Balances greater than 12 months include investments that were in an immaterial unrealized loss position as of December 31, 2013.
	(2)	Balances less than 12 months include investments that were in an immaterial unrealized loss position as of December 31, 2013.

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Assets measured at fair value on a recurring basis	'
	The following tables provide a summary of assets and liabilities measured at fair value on a recurring basis and as reported in the Condensed Consolidated Balance Sheets (in millions):
		Fair Value Measurements at March 31, 2014 Using:
		Quoted Prices in		Significant Other			Significant Other
		Active Markets For		Observable			Unobservable
		Identical Assets		Remaining Inputs			Remaining Inputs
		(Level 1)		(Level 2)			(Level 3)		Total
	Assets measured at fair value:
	Available-for-sale securities:
	Asset-backed securities	$	—	$	135.3		$	—	$	135.3
	Certificates of deposit	—		12			—		12
	Commercial paper	—		1.2			—		1.2
	Corporate debt securities	—		412.2			—		412.2
	Foreign government debt securities	—		5			—		5
	Government-sponsored enterprise obligations	—		88.3			—		88.3
	Money market funds(1)	1,183.00		—			—		1,183.00
	Mutual funds(2)	4.1		—			—		4.1
	Publicly-traded equity securities	6.4		—			—		6.4
	U.S. government securities	140.9		100.7			—		241.6
	Total available-for-sale securities	1,334.40		754.7			—		2,089.10
	Trading securities in mutual funds(3)	16.1		—			—		16.1
	Derivative assets:
	Foreign exchange contracts	—		3.7			—		3.7
	Total assets measured at fair value	$	1,350.50	$	758.4		$	—	$	2,108.90
	Liabilities measured at fair value:
	Derivative liabilities:
	Foreign exchange contracts	$	—	$	(0.1	)	$	—	$	(0.1	)
	Total liabilities measured at fair value	$	—	$	(0.1	)	$	—	$	(0.1	)
	Total assets measured at fair value, reported as:
	Cash equivalents	$	1,116.30	$	18.8		$	—	$	1,135.10
	Restricted investments	70.8		—			—		70.8
	Short-term investments	135.7		242.4			—		378.1
	Long-term investments	27.7		493.5			—		521.2
	Prepaid expenses and other current assets	—		3.7			—		3.7
	Total assets measured at fair value	$	1,350.50	$	758.4		$	—	$	2,108.90
	Total liabilities measured at fair value, reported as:
	Other accrued liabilities	$	—	$	(0.1	)	$	—	$	(0.1	)
	Total liabilities measured at fair value	$	—	$	(0.1	)	$	—	$	(0.1	)
	________________________________
	(1)	Balance includes $66.7 million of restricted investments measured at fair market value related to the Company's D&O Trust and acquisitions related escrows.
	(2)	Balance relates to restricted investments measured at fair market value related to the Company's India Gratuity Trust.
	(3)	Balance relates to investments measured at fair value related to the Company's non-qualified deferred compensation plan assets.
		Fair Value Measurements at December 31, 2013 Using:
		Quoted Prices in		Significant Other			Significant Other
		Active Markets For		Observable			Unobservable
		Identical Assets		Remaining Inputs			Remaining Inputs
		(Level 1)		(Level 2)			(Level 3)		Total
	Assets measured at fair value:
	Available-for-sale securities:
	Asset-backed securities	$	—	$	249.9		$	—	$	249.9
	Certificates of deposit	—		27.6			—		27.6
	Commercial paper	—		6.9			—		6.9
	Corporate debt securities	—		815.3			—		815.3
	Foreign government debt securities	—		10.7			—		10.7
	Government-sponsored enterprise obligations	—		306.2			—		306.2
	Money market funds(1)	1,043.70		—			—		1,043.70
	Mutual funds(2)	4		—			—		4
	Publicly-traded equity securities	114.6		—			—		114.6
	U.S. government securities	197.2		106.1			—		303.3
	Total available-for-sale securities	1,359.50		1,522.70			—		2,882.20
	Trading securities in mutual funds(3)	15.4		—			—		15.4
	Derivative assets:
	Foreign exchange contracts	—		3			—		3
	Total assets measured at fair value	$	1,374.90	$	1,525.70		$	—	$	2,900.60
Liabilities measured at fair value:
Derivative liabilities:
Foreign exchange contracts	$	—	$	(0.7	)	$	—	$	(0.7	)
Total liabilities measured at fair value	$	—	$	(0.7	)	$	—	$	(0.7	)
Total assets measured at fair value, reported as:
Cash equivalents	$	965.1	$	31.1		$	—	$	996.2
Restricted investments	87.6		—			—		87.6
Short-term investments	246.5		315.4			—		561.9
Long-term investments	75.7		1,176.20			—		1,251.90
Prepaid expenses and other current assets	—		3			—		3
Total assets measured at fair value	$	1,374.90	$	1,525.70		$	—	$	2,900.60
Total liabilities measured at fair value, reported as:
Other accrued liabilities	$	—	$	(0.7	)	$	—	$	(0.7	)
Total liabilities measured at fair value	$	—	$	(0.7	)	$	—	$	(0.7	)
________________________________
(1)	Balance includes $83.6 million of restricted investments measured at fair market value related to the Company's D&O Trust and acquisitions related escrows.
(2)	Balance relates to restricted investments measured at fair market value related to the Company's India Gratuity Trust.
(3)	Balance relates to investments measured at fair value related to the Company's non-qualified deferred compensation plan assets.

Derivative_Instruments_Tables

Derivative Instruments (Tables)	3 Months Ended
	Mar. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivative instruments	'
	The notional amount of the Company's foreign currency derivatives are summarized as follows (in millions):
		As of
		March 31,		December 31,
		2014		2013
	Cash flow hedges	$	117.1	$	137.6
	Non-designated derivatives	153.8		144.4
	Total	$	270.9	$	282

Goodwill_and_Purchased_Intangi1

Goodwill and Purchased Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]	'
Goodwill	'
	The following table presents goodwill activity during the three months ended March 31, 2014 (in millions):
	Balance as of December 31, 2013	$	4,057.70
	Additions due to business combinations	13.6
	Balance as of March 31, 2014	$	4,071.30
Finite-lived intangible assets by major class	'
	The Company’s purchased intangible assets were as follows (in millions):
		Gross		Accumulated			Impairments and			Net
				Amortization			Other Charges
	As of March 31, 2014
	Intangible assets with finite lives:
	Technologies and patents	$	592.1	$	(461.9	)	$	(30.5	)	$	99.7
	Customer contracts, support agreements, and	80.3		(63.7		)	(2.2		)	14.4
	related relationships
	Other	1.1		(0.1		)	—			1
	Total purchased intangible assets	$	673.5	$	(525.7	)	$	(32.7	)	$	115.1
	As of December 31, 2013
	Intangible assets with finite lives:
	Technologies and patents	$	581.4	$	(453.4	)	$	(30.5	)	$	97.5
	Customer contracts, support agreements, and	74.3		(62.7		)	(2.2		)	9.4
	related relationships
	Total purchased intangible assets	$	655.7	$	(516.1	)	$	(32.7	)	$	106.9
Amortization of intangible assets included in the Condensed Consolidated Statements of Operations	'
	The following table presents the amortization of intangible assets included in the Condensed Consolidated Statements of Operations (in millions):
		Three Months Ended March 31,
		2014		2013
	Cost of revenues	$	8.2	$	6.3
	Operating expenses:
	Sales and marketing	1		0.9
	General and administrative	0.3		0.3
	Total operating expenses	1.3		1.2
	Total	$	9.5	$	7.5
Estimated future amortization expense of purchased intangible assets with finite lives	'
	As of March 31, 2014, the estimated future amortization expense of purchased intangible assets with finite lives is as follows (in millions):
	Years Ending December 31,	Amount
	Remainder of 2014	$	29.3
	2015	35.3
	2016	21.1
	2017	13
	2018	6.1
	Thereafter	10.3
	Total	$	115.1

Other_Financial_Information_Ta

Other Financial Information (Tables)	3 Months Ended
	Mar. 31, 2014
Other Financial Information [Abstract]	'
Inventories	'
	Inventories are reported within prepaid expenses and other current assets and other long-term assets in the Condensed Consolidated Balance Sheets and consisted of the following (in millions):
		As of
		March 31,			December 31,
		2014			2013
	Production materials	$	53.5		$	51.3
	Finished goods	1.2			1.4
	Inventories	$	54.7		$	52.7
Other long-term assets	'
	Other long-term assets consisted of the following (in millions):
		As of
		March 31,			December 31,
		2014			2013
	Privately-held investments	$	58.7		$	57.2
	Licensed software	9.5			90.4
	Federal income tax receivable	20			20
	Financed customer receivable	20.9			19.9
	Inventory	14.9			15.2
	Prepaid costs, deposits, and other	34.9			31.1
	Other long-term assets	$	158.9		$	233.8
Warranties	'
	Changes in the Company’s warranty reserve during the three months ended March 31, 2014 were as follows (in millions):
	Balance as of December 31, 2013	$	28
	Provisions made during the period, net	7.3
	Adjustments related to pre-existing warranties	—
	Actual costs incurred during the period	(6.9		)
	Balance as of March 31, 2014	$	28.4
Deferred revenue	'
	Details of the Company's deferred revenue, as reported on the Condensed Consolidated Balance Sheets, were as follows (in millions):
		As of
		March 31,			December 31,
		2014			2013
	Deferred product revenue:
	Undelivered product commitments and other product deferrals	$	186.3		$	184.9
	Distributor inventory and other sell-through items	93.8			118.7
	Deferred gross product revenue	280.1			303.6
	Deferred cost of product revenue	(48.9		)	(58.6		)
	Deferred product revenue, net	231.2			245
	Deferred service revenue	923			824.3
	Total	$	1,154.20		$	1,069.30
	Reported as:
	Current	$	772.5		$	705.8
	Long-term	381.7			363.5
	Total	$	1,154.20		$	1,069.30
Other income (expense), net	'
	Other income (expense), net, consisted of the following (in millions):
		Three Months Ended March 31,
		2014			2013
	Interest income	$	2.1		$	2.1
	Interest expense	(15.4		)	(14.3		)
	Other	167.5			2.1
	Other income (expense), net	$	154.2		$	(10.1	)

Restructuring_and_Other_Charge1

Restructuring and Other Charges (Tables)	3 Months Ended
	Mar. 31, 2014
Restructuring Charges [Abstract]	'
Summary of restructuring and other charges	'
	The following table presents restructuring and other charges included in cost of revenues and restructuring and other charges in the Condensed Consolidated Statements of Operations under the Company's restructuring plans (in millions):
		Three Months Ended March 31,
		2014		2013
	Severance	$	28.3	$	4.4
	Facilities	0.2		2.6
	Contract terminations	0.8		0.7
	Asset impairment and write-downs	93.1		—
	Total	$	122.4	$	7.7
	Reported as:
	Cost of revenues	$	8.4	$	0.7
	Restructuring and other charges	114		7
	Total	$	122.4	$	7.7
Changes in restructuring liability	'
	The following table provides a summary of changes in the restructuring liability related to the Company's plans during the three months ended March 31, 2014 (in millions):
		December 31,		Charges		Cash			Non-cash			March 31,
		2013				Payments			Settlements and			2014
									Other
	Severance	$	5.6	$	28.3	$	(3.7	)	$	(0.6	)	$	29.6
	Facilities	5.1		0.2		(0.9		)	—			4.4
	Contract terminations and other	7.1		0.8		(7.0		)	(0.8		)	0.1
	Total	$	17.8	$	29.3	$	(11.6	)	$	(1.4	)	$	34.1

LongTerm_Debt_and_Financing_Ta

Long-Term Debt and Financing (Tables)	3 Months Ended
	Mar. 31, 2014
Debt Instruments [Abstract]	'
Long-term debt	'
	The following table summarizes the Company's long-term debt (in millions, except percentages):
		As of March 31, 2014
		Amount			Effective Interest
					Rates
	Senior notes:
	3.10% fixed-rate notes, due 2016 ("2016 Notes")	$	300		3.25	%
	4.60% fixed-rate notes, due 2021 ("2021 Notes")	300			4.69	%
	4.50% fixed-rate notes, due 2024 ("2024 Notes")	350			4.63	%
	5.95% fixed-rate notes, due 2041 ("2041 Notes")	400			6.03	%
	Total senior notes	1,350.00
	Unaccreted discount	(1.1		)
	Total	$	1,348.90

Equity_Tables

Equity (Tables)	3 Months Ended
	Mar. 31, 2014
Stockholders' Equity Note [Abstract]	'
Components of accumulated other comprehensive income, net of taxes	'
	The components of accumulated other comprehensive income, net of related taxes, during the three months ended March 31, 2014 were as follows (in millions):
		Unrealized			Unrealized			Foreign			Total
		Gains (Losses)			Gains (Losses)			Currency
		on Available-for-			on Cash Flow			Translation
		Sale Securities(1)			Hedges(2)			Adjustments
	Balance as of December 31, 2013	$	66.2		$	2.2		$	(3.8	)	$	64.6
	Other comprehensive gain before reclassifications	38.1			2.1			1.7			41.9
	Amount reclassified from accumulated other	(103.5		)	(1.1		)	—			(104.6		)
	comprehensive income
	Net other comprehensive loss	(65.4		)	1			1.7			(62.7		)
	Balance as of March 31, 2014	$	0.8		$	3.2		$	(2.1	)	$	1.9
	________________________________
	(1)	The reclassifications out of accumulated other comprehensive income during the three months ended March 31, 2014 for realized gains on available-for-sale securities of $103.5 million are included in other income (expense), net, in the Condensed Consolidated Statements of Operations.
	(2)	The reclassifications out of accumulated other comprehensive income during the three months ended March 31, 2014 for realized gains on cash flow hedges are included within cost of revenues of $0.2 million, sales and marketing of $1.1 million, and general and administrative of $0.1 million and for realized losses of $0.3 million within research and development for which the hedged transactions relate in the Condensed Consolidated Statements of Operations.

Employee_Benefit_Plans_Tables

Employee Benefit Plans (Tables)	3 Months Ended
	Mar. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Schedule of share-based compensation, stock options, activity	'
	The following table summarizes the Company’s stock option activity and related information as of and for the three months ended March 31, 2014 (in millions, except for per share amounts and years):
		Outstanding Options
		Number of Shares			Weighted Average			Weighted Average	Aggregate
					Exercise Price			Remaining	Intrinsic
					per Share			Contractual Term	Value
								(In Years)
	Balance as of December 31, 2013	23.1			$	25.15
	Canceled	(0.3	)		30.34
	Exercised	(3.7	)		20.24
	Expired	(0.6	)		28.76
	Balance as of March 31, 2014	18.5			$	25.92		2.2	$	52.9
	As of March 31, 2014:
	Vested and expected-to-vest options	18.2			$	26.04		2.1	$	50.1
	Exercisable options	16.7			$	26.48		1.8	$	36.3
Schedule of nonvested share activity	'
	The following table summarizes the Company’s RSU, RSA, and PSA activity and related information as of and for the three months ended March 31, 2014 (in millions, except per share amounts and years):
		Outstanding RSUs, RSAs, and PSAs
		Number of Shares			Weighted Average			Weighted Average	Aggregate
					Grant-Date Fair			Remaining	Intrinsic
					Value per Share			Contractual Term	Value
								(In Years)
	Balance as of December 31, 2013	25.4			$	23.44
	RSUs granted (1)(4)	1.9			22.14
	RSUs assumed (2)	0.4			22.66
	RSAs assumed (2)	0.9			22.66
	PSAs granted (3)(4)	0.8			25.22
	PSAs assumed (2)	0.2			22.66
	RSUs vested	(4.6	)		24.05
	RSAs vested	(0.3	)		19.59
	PSAs vested	(1.0	)		38.1
	RSUs canceled	(0.5	)		21.55
	PSAs canceled	(2.1	)		33.85
	Balance as of March 31, 2014	21.1			$	21.57		1.4	$	543.3
	________________________________
	(1)	Includes service-based and market-based RSUs granted under the 2006 Plan according to its terms.
	(2)	RSUs, RSAs, and PSAs assumed in connection with the acquisition of WANDL.
	(3)	The number of shares subject to PSAs granted represents the aggregate maximum number of shares that may be issued pursuant to the award over its full term. The aggregate number of shares subject to these PSAs that would be issued if performance goals determined by the Compensation Committee are achieved at target is 0.4 million shares. Depending on achievement of such performance goals, the range of shares that could be issued under these awards is 0 to 0.8 million shares.
	(4)	On February 20, 2014, the Company announced its intention to initiate a quarterly cash dividend of $0.10 per share of common stock in the third quarter of 2014. As a result of the Company's announcement, the grant date fair value of RSUs and PSAs granted after the announcement date were reduced by the present value of the dividends expected to be paid on the underlying shares of common stock during the requisite and derived service period as these awards are not entitled to receive dividends until vested.
Estimates of weighted average fair value per share under employee purchase plan and stock option plan	'
	The weighted-average assumptions used and the resulting estimates of fair value for ESPP and market-based RSUs were as follows:
		Three Months Ended March 31,
		2014		2013
	ESPP (1):
	Volatility	33%		36%
	Risk-free interest rate	0.10%		0.10%
	Expected life (years)	0.5		0.5
	Dividend yield	—		—
	Weighted-average fair value per share	$6.37		$5.63
	Market-based RSUs (2):
	Volatility	36%		—
	Risk-free interest rate	1.60%		—
	Dividend yield	0% - 1.5%		—
	Weighted-average fair value per share	$18.28		—
	________________________________
	(1)	The Black-Scholes-Merton option-pricing model is utilized to estimate the fair value of ESPP.
	(2)	The fair value of market-based RSUs utilizes a Monte Carlo valuation methodology. The Company amortizes the fair value of these awards over the derived service period adjusted for estimated forfeitures for each separately vesting tranche of the award. Provided that the derived service is rendered, the total fair value of the market-based RSUs at the date of grant is recognized as compensation expense even if the market condition is not achieved. However, the number of shares that ultimately vest can vary significantly with the performance of the specified market criteria.
Schedule of employee service share-based compensation, allocation of recognized period costs	'
	Share-based compensation expense associated with stock options, RSUs, RSAs, PSAs, and ESPP was recorded in the following cost and expense categories in the Condensed Consolidated Statements of Operations (in millions):
		Three Months Ended March 31,
		2014				2013
	Cost of revenues - Product	$	1.3			$	0.9
	Cost of revenues - Service	4				4.6
	Research and development	32.1				23.6
	Sales and marketing	14.6				14.5
	General and administrative	8.8				6.3
	Total	$	60.8			$	49.9
Disclosure of share-based compensation arrangements by share-based payment award	'
	The following table summarizes share-based compensation expense by award type (in millions):
		Three Months Ended March 31,
		2014				2013
	Stock options	$	5.1			$	9.5
	RSUs, RSAs, and PSAs	51.8				37
	ESPP	3.9				3.4
	Total	$	60.8			$	49.9
Schedule of unrecognized compensation cost, nonvested awards	'
	The following table presents unrecognized compensation cost, adjusted for estimated forfeitures, recognized over a weighted-average period related to unvested stock options, RSUs, RSAs, and PSAs as of March 31, 2014 (in millions, except years):
		Unrecognized				Weighted Average
		Compensation Cost				Period
						(In Years)
	Stock options	$	25.9			1.7
	RSUs, RSAs, and PSAs	$	293.1			2

Segments_Tables

Segments (Tables)	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Financial information for each segment	'
	The following table presents net revenues by product and service (in millions):
		Three Months Ended March 31,
		2014		2013
	Routing	$	549.8	$	513.6
	Switching	192		131.5
	Security	134.2		136.7
	Total product	876		781.8
	Total service	294.1		277.4
	Total	$	1,170.10	$	1,059.20
Net revenues by geographic region	'
	The Company attributes revenues to geographic region based on the customer’s ship-to location. The following table presents net revenues by geographic region (in millions):
		Three Months Ended March 31,
		2014		2013
	Americas:
	United States	$	623.7	$	547
	Other	57.8		45.1
	Total Americas	681.5		592.1
	Europe, Middle East, and Africa	295.7		290.6
	Asia Pacific	192.9		176.5
	Total	$	1,170.10	$	1,059.20

Income_Taxes_Tables

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2014
Income Tax Disclosure [Abstract]	'
Schedule of effective income tax rate reconciliation	'
	The effective tax rates for the three months ended March 31, 2014 and March 31, 2013 include the tax expense (benefit) of the following discrete items (in millions):
		Three Months Ended March 31,
		2014			2013
	Tax on gain of equity investments, net of valuation allowance release of $24.7	$	35.6		$	—
	Benefit from restructuring costs	$	(30.8	)	$	—
	Tax settlement with Internal Revenue Service (“IRS”)	$	—		$	(27.8	)
	Reinstatement of the U.S. federal R&D tax credit	$	—		$	(15.2	)

Net_Income_per_Share_Tables

Net Income per Share (Tables)	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Schedule of earnings per share, basic and diluted	'
	The Company computed basic and diluted net income per share as follows (in millions, except per share amounts):
		Three Months Ended March 31,
		2014		2013
	Numerator:
	Net income	$	110.6	$	91
	Denominator:
	Weighted-average shares used to compute	486.2		504.7
	basic net income per share
	Dilutive effect of employee stock awards	10.3		8
	Weighted-average shares used to compute	496.5		512.7
	diluted net income per share
	Net income per share:
	Basic	$	0.23	$	0.18
	Diluted	$	0.22	$	0.18
	Anti-dilutive:
	Potential anti-dilutive shares	25.4		24.7

Business_Combinations_Intangib

Business Combinations, Intangible Assets Acquired (Details) (WANDL, Inc, [Member], USD $)	0 Months Ended
In Millions, unless otherwise specified	Jan. 07, 2014
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill [Abstract]	'
Weighted Average Estimated Useful Life (In Years)	'7 years
Amount	$17.80
Existing Technology [Member]	'
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill [Abstract]	'
Weighted Average Estimated Useful Life (In Years)	'7 years
Amount	10.7
Customer Relationships [Member]	'
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill [Abstract]	'
Weighted Average Estimated Useful Life (In Years)	'7 years
Amount	6
Trade Names [Member]	'
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill [Abstract]	'
Weighted Average Estimated Useful Life (In Years)	'4 years
Amount	0.6
Order or Production Backlog [Member]	'
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill [Abstract]	'
Weighted Average Estimated Useful Life (In Years)	'1 year
Amount	0.2
Noncompete Agreements [Member]	'
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill [Abstract]	'
Weighted Average Estimated Useful Life (In Years)	'2 years
Amount	$0.30

Business_Combination_Narrative

Business Combination, Narrative (Details) (USD $)	3 Months Ended			0 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Jan. 07, 2014
				WANDL, Inc, [Member]
Business Acquisition [Line Items]	'	'	'	'
Percentage of voting interests acquired	'	'	'	100.00%
Consideration transferred	'	'	'	$28.70
Intangible assets acquired	'	'	'	17.8
Goodwill	4,071.30	'	4,057.70	13.6
Net liabilities assumed	'	'	'	-2.7
Share-based awards assumed, fair value	'	'	'	34.9
Business combination, acquisition related costs	$0.60	$0.10	'	'

Cash_Equivalents_and_Investmen2

Cash Equivalents and Investments - Available-For-Sale and Trading Securities (Details) (USD $)	Mar. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Available-for-sale securities:	'		'
Available-for-sale securities, amortized cost	$2,088.60		$2,777.80
Available-for-sale securities, gross unrealized gains	1.5		106.9
Available-for-sale securities, gross unrealized losses	-1		-2.5
Available-for-sale securities, estimated fair value	2,089.10		2,882.20
Trading securities:	'		'
Trading securities, amortized cost	16.1	[1]	15.4	[1]
Trading securities, gross unrealized gains	0	[1]	0	[1]
Trading securities, gross unrealized losses	0	[1]	0	[1]
Trading securities, estimated fair value	16.1	[1]	15.4	[1]
Available-for-sale and Trading Securities [Abstract]	'		'
Total investments, amortized cost	2,104.70		2,793.20
Total investments, gross unrealized gains	1.5		106.9
Total investments, gross unrealized losses	-1		-2.5
Total investments, estimated fair value	2,105.20		2,897.60
Cash equivalents [Member]	'		'
Available-for-sale and Trading Securities [Abstract]	'		'
Total investments, amortized cost	1,135.10		996.2
Total investments, gross unrealized gains	0		0
Total investments, gross unrealized losses	0		0
Total investments, estimated fair value	1,135.10		996.2
Restricted investments [Member]	'		'
Available-for-sale and Trading Securities [Abstract]	'		'
Total investments, amortized cost	70.7		87.5
Total investments, gross unrealized gains	0.1		0.1
Total investments, gross unrealized losses	0		0
Total investments, estimated fair value	70.8		87.6
Short-term investments [Member]	'		'
Available-for-sale and Trading Securities [Abstract]	'		'
Total investments, amortized cost	378.6		459
Total investments, gross unrealized gains	0.3		104.9
Total investments, gross unrealized losses	-0.8		-2
Total investments, estimated fair value	378.1		561.9
Long-term investments [Member]	'		'
Available-for-sale and Trading Securities [Abstract]	'		'
Total investments, amortized cost	520.3		1,250.50
Total investments, gross unrealized gains	1.1		1.9
Total investments, gross unrealized losses	-0.2		-0.5
Total investments, estimated fair value	521.2		1,251.90
Debt Securities [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities, amortized cost	894.4		1,718.20
Available-for-sale securities, gross unrealized gains	1.4		2.3
Available-for-sale securities, gross unrealized losses	-0.2		-0.6
Available-for-sale securities, estimated fair value	895.6		1,719.90
Asset-backed securities [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities, amortized cost	135.4		249.9
Available-for-sale securities, gross unrealized gains	0		0.1
Available-for-sale securities, gross unrealized losses	-0.1		-0.1
Available-for-sale securities, estimated fair value	135.3		249.9
Certificates of deposit [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities, amortized cost	12		27.6
Available-for-sale securities, gross unrealized gains	0		0
Available-for-sale securities, gross unrealized losses	0		0
Available-for-sale securities, estimated fair value	12		27.6
Commercial paper [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities, amortized cost	1.2		6.9
Available-for-sale securities, gross unrealized gains	0		0
Available-for-sale securities, gross unrealized losses	0		0
Available-for-sale securities, estimated fair value	1.2		6.9
Corporate debt securities [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities, amortized cost	411		813.6
Available-for-sale securities, gross unrealized gains	1.3		2
Available-for-sale securities, gross unrealized losses	-0.1		-0.3
Available-for-sale securities, estimated fair value	412.2		815.3
Foreign government debt securities [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities, amortized cost	5		10.7
Available-for-sale securities, gross unrealized gains	0		0
Available-for-sale securities, gross unrealized losses	0		0
Available-for-sale securities, estimated fair value	5		10.7
Government-sponsored enterprise obligations [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities, amortized cost	88.3		306.2
Available-for-sale securities, gross unrealized gains	0		0.1
Available-for-sale securities, gross unrealized losses	0		-0.1
Available-for-sale securities, estimated fair value	88.3		306.2
US government securities [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities, amortized cost	241.5		303.3
Available-for-sale securities, gross unrealized gains	0.1		0.1
Available-for-sale securities, gross unrealized losses	0		-0.1
Available-for-sale securities, estimated fair value	241.6		303.3
Money market funds [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities, amortized cost	1,183		1,043.70
Available-for-sale securities, gross unrealized gains	0		0
Available-for-sale securities, gross unrealized losses	0		0
Available-for-sale securities, estimated fair value	1,183		1,043.70
Mutual funds [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities, amortized cost	4		3.9
Available-for-sale securities, gross unrealized gains	0.1		0.1
Available-for-sale securities, gross unrealized losses	0		0
Available-for-sale securities, estimated fair value	4.1		4
Publicly-traded equity securities [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities, amortized cost	7.2		12
Available-for-sale securities, gross unrealized gains	0		104.5
Available-for-sale securities, gross unrealized losses	-0.8		-1.9
Available-for-sale securities, estimated fair value	$6.40		$114.60
[1]	Balance includes the Company's non-qualified deferred compensation plan assets.

Cash_Equivalents_and_Investmen3

Cash Equivalents and Investments - Maturities of Fixed Income Investments (Details) (USD $)	Mar. 31, 2014
In Millions, unless otherwise specified
Schedule of Fixed Income Securities Maturities [Abstract]	'
Amortized cost due within one year	$374
Gross unrealized gains due within one year	0.3
Gross unrealized losses due within one year	0
Estimated fair value due within one year	374.3
Amortized cost due between one and five years	520.4
Gross unrealized gains due between one and five years	1.1
Gross unrealized losses due between one and five year	-0.2
Estimated fair value due between one and five year	521.3
Total investments, amortized cost	894.4
Gross Unrealized Gains	1.4
Gross Unrealized Losses	-0.2
Total investments, estimated fair value	$895.60

Cash_Equivalents_and_Investmen4

Cash Equivalents and Investments - Unrealized Loss on Available-for-Sale Securities (Details) (USD $)	3 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]	'		'
Fair value, less than 12 months	$168.20		$568.70
Unrealized loss, less than 12 months	-1		-2.5
Fair value, 12 months or greater	11		10.3
Unrealized loss, 12 months or greater	0		0
Total fair value, available-for-sale investments in continuous unrealized loss position	179.2		579
Total unrealized loss, available-for-sale investments in continuous unrealized loss position	-1		-2.5
Debt Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Fair value, less than 12 months	161.8		561.9
Unrealized loss, less than 12 months	-0.2		-0.6
Fair value, 12 months or greater	11		10.3
Unrealized loss, 12 months or greater	0		0
Total fair value, available-for-sale investments in continuous unrealized loss position	172.8		572.2
Total unrealized loss, available-for-sale investments in continuous unrealized loss position	-0.2		-0.6
Asset-backed securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Fair value, less than 12 months	65.9	[1]	153	[2]
Unrealized loss, less than 12 months	-0.1	[1]	-0.1	[2]
Fair value, 12 months or greater	6	[1]	0.6	[2]
Unrealized loss, 12 months or greater	0	[1]	0	[2]
Total fair value, available-for-sale investments in continuous unrealized loss position	71.9	[1]	153.6	[2]
Total unrealized loss, available-for-sale investments in continuous unrealized loss position	-0.1	[1]	-0.1	[2]
Corporate debt securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Fair value, less than 12 months	54.1		156.1	[2]
Unrealized loss, less than 12 months	-0.1		-0.3	[2]
Fair value, 12 months or greater	0		9.7	[2]
Unrealized loss, 12 months or greater	0		0	[2]
Total fair value, available-for-sale investments in continuous unrealized loss position	54.1		165.8	[2]
Total unrealized loss, available-for-sale investments in continuous unrealized loss position	-0.1		-0.3	[2]
Foreign government debt securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Fair value, less than 12 months	0	[1]	10	[3]
Unrealized loss, less than 12 months	0	[1]	0	[3]
Fair value, 12 months or greater	5	[1]	0	[3]
Unrealized loss, 12 months or greater	0	[1]	0	[3]
Total fair value, available-for-sale investments in continuous unrealized loss position	5	[1]	10	[3]
Total unrealized loss, available-for-sale investments in continuous unrealized loss position	0	[1]	0	[3]
Government-sponsored enterprise obligations [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Fair value, less than 12 months	34.9	[4]	123.1
Unrealized loss, less than 12 months	0	[4]	-0.1
Fair value, 12 months or greater	0	[4]	0
Unrealized loss, 12 months or greater	0	[4]	0
Total fair value, available-for-sale investments in continuous unrealized loss position	34.9	[4]	123.1
Total unrealized loss, available-for-sale investments in continuous unrealized loss position	0	[4]	-0.1
US government securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Fair value, less than 12 months	6.9	[4]	119.7
Unrealized loss, less than 12 months	0	[4]	-0.1
Fair value, 12 months or greater	0	[4]	0
Unrealized loss, 12 months or greater	0	[4]	0
Total fair value, available-for-sale investments in continuous unrealized loss position	6.9	[4]	119.7
Total unrealized loss, available-for-sale investments in continuous unrealized loss position	0	[4]	-0.1
Publicly-traded equity securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Fair value, less than 12 months	6.4		6.8
Unrealized loss, less than 12 months	-0.8		-1.9
Fair value, 12 months or greater	0		0
Unrealized loss, 12 months or greater	0		0
Total fair value, available-for-sale investments in continuous unrealized loss position	6.4		6.8
Total unrealized loss, available-for-sale investments in continuous unrealized loss position	($0.80)		($1.90)
[1]	Balances greater than 12 months include investments that were in an immaterial unrealized loss position as of MarchB 31, 2014.
[2]	Balances greater than 12 months include investments that were in an immaterial unrealized loss position as of DecemberB 31, 2013.
[3]	Balances less than 12 months include investments that were in an immaterial unrealized loss position as of DecemberB 31, 2013.
[4]	Balances less than 12 months include investments that were in an immaterial unrealized loss position as of MarchB 31, 2014.

Cash_Equivalents_and_Investmen5

Cash Equivalents, and Investments, Narrative (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
	Investment		Investment
Cash Equivalents and Investments [Abstract]	'	'	'
Cost-method Investments, Other than Temporary Impairment	$0	$0	'
Total investments in unrealized loss position	95	'	178
Other-than-temporary impairment losses, available-for-sale securities	1.6	'	'
Available-for-sale securities, gross realized gains	165.5	'	'
Privately-held investments	$58.70	'	$57.20

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)	Mar. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Available-for-sale securities:	'		'
Available-for-sale securities	$2,089.10		$2,882.20
Trading securities:	'		'
Trading securities	16.1	[1]	15.4	[1]
Fair Value Measurements (Textuals)	'		'
Restricted investments	66.7		83.6
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Derivative assets:	'		'
Total assets measured at fair value	2,108.90		2,900.60
Liabilities measured at fair value:	'		'
Other accrued liabilities	-0.1		-0.7
Total liabilities measured at fair value	-0.1		-0.7
Cash equivalents	1,135.10		996.2
Restricted investments measured at fair value	70.8		87.6
Short-term investments measured at fair value	378.1		561.9
Long-term investments measured at fair value	521.2		1,251.90
Prepaid expenses and other current assets measured at fair value	3.7		3
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Derivative assets:	'		'
Total assets measured at fair value	1,350.50		1,374.90
Liabilities measured at fair value:	'		'
Other accrued liabilities	0		0
Total liabilities measured at fair value	0		0
Cash equivalents	1,116.30		965.1
Restricted investments measured at fair value	70.8		87.6
Short-term investments measured at fair value	135.7		246.5
Long-term investments measured at fair value	27.7		75.7
Prepaid expenses and other current assets measured at fair value	0		0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Derivative assets:	'		'
Total assets measured at fair value	758.4		1,525.70
Liabilities measured at fair value:	'		'
Other accrued liabilities	-0.1		-0.7
Total liabilities measured at fair value	-0.1		-0.7
Cash equivalents	18.8		31.1
Restricted investments measured at fair value	0		0
Short-term investments measured at fair value	242.4		315.4
Long-term investments measured at fair value	493.5		1,176.20
Prepaid expenses and other current assets measured at fair value	3.7		3
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Derivative assets:	'		'
Total assets measured at fair value	0		0
Liabilities measured at fair value:	'		'
Other accrued liabilities	0		0
Total liabilities measured at fair value	0		0
Cash equivalents	0		0
Restricted investments measured at fair value	0		0
Short-term investments measured at fair value	0		0
Long-term investments measured at fair value	0		0
Prepaid expenses and other current assets measured at fair value	0		0
Foreign exchange contract [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Derivative assets:	'		'
Derivative assets	3.7		3
Liabilities measured at fair value:	'		'
Derivative liabilities	-0.1		-0.7
Foreign exchange contract [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Derivative assets:	'		'
Derivative assets	0		0
Liabilities measured at fair value:	'		'
Derivative liabilities	0		0
Foreign exchange contract [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Derivative assets:	'		'
Derivative assets	3.7		3
Liabilities measured at fair value:	'		'
Derivative liabilities	-0.1		-0.7
Foreign exchange contract [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Derivative assets:	'		'
Derivative assets	0		0
Liabilities measured at fair value:	'		'
Derivative liabilities	0		0
Asset-backed Securities [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	135.3		249.9
Asset-backed Securities [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	135.3		249.9
Asset-backed Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	0		0
Asset-backed Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	135.3		249.9
Asset-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	0		0
Certificates of deposit [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	12		27.6
Certificates of deposit [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	12		27.6
Certificates of deposit [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	0		0
Certificates of deposit [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	12		27.6
Certificates of deposit [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	0		0
Commercial paper [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	1.2		6.9
Commercial paper [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	1.2		6.9
Commercial paper [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	0		0
Commercial paper [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	1.2		6.9
Commercial paper [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	0		0
Corporate debt securities [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	412.2		815.3
Corporate debt securities [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	412.2		815.3
Corporate debt securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	0		0
Corporate debt securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	412.2		815.3
Corporate debt securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	0		0
Foreign government debt securities [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	5		10.7
Foreign government debt securities [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	5		10.7
Foreign government debt securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	0		0
Foreign government debt securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	5		10.7
Foreign government debt securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	0		0
Government-sponsored enterprise obligations [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	88.3		306.2
Government-sponsored enterprise obligations [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	88.3		306.2
Government-sponsored enterprise obligations [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	0		0
Government-sponsored enterprise obligations [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	88.3		306.2
Government-sponsored enterprise obligations [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	0		0
Money market funds [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	1,183		1,043.70
Money market funds [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	1,183	[2]	1,043.70	[3]
Money market funds [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	1,183	[2]	1,043.70	[3]
Money market funds [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	0	[2]	0	[3]
Money market funds [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	0	[2]	0	[3]
Mutual funds [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	4.1		4
Mutual funds [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	4.1	[4]	4	[4]
Trading securities:	'		'
Trading securities	16.1	[5]	15.4	[5]
Mutual funds [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	4.1	[4]	4	[4]
Trading securities:	'		'
Trading securities	16.1	[5]	15.4	[5]
Mutual funds [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	0	[4]	0	[4]
Trading securities:	'		'
Trading securities	0	[5]	0	[5]
Mutual funds [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	0	[4]	0	[4]
Trading securities:	'		'
Trading securities	0	[5]	0	[5]
Publicly-traded equity securities [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	6.4		114.6
Publicly-traded equity securities [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	6.4		114.6
Publicly-traded equity securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	6.4		114.6
Publicly-traded equity securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	0		0
Publicly-traded equity securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	0		0
US government securities [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	241.6		303.3
US government securities [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	241.6		303.3
US government securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	140.9		197.2
US government securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	100.7		106.1
US government securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	0		0
Available-for-sale securities [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	2,089.10		2,882.20
Available-for-sale securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	1,334.40		1,359.50
Available-for-sale securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	754.7		1,522.70
Available-for-sale securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]	'		'
Available-for-sale securities:	'		'
Available-for-sale securities	$0		$0
[1]	Balance includes the Company's non-qualified deferred compensation plan assets.
[2]	Balance includes $66.7 million of restricted investments measured at fair market value related to the Company's D&O Trust and acquisitions related escrows.
[3]	Balance includes $83.6 million of restricted investments measured at fair market value related to the Company's D&O Trust and acquisitions related escrows.
[4]	Balance relates to restricted investments measured at fair market value related to the Company's India Gratuity Trust.
[5]	Balance relates to investments measured at fair value related to the Company's non-qualified deferred compensation plan assets.

Fair_Value_Measurements_Narrat

Fair Value Measurements - Narrative (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Fair Value, Inputs, Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Long-term debt, fair value	$1,398,600,000	$1,023,500,000
Cost Method Investment, Privately Held Companies [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cost method measured at fair value	$0	$2,000,000

Derivative_Instruments_Details

Derivative Instruments (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Derivatives, Fair Value [Line Items]	'	'
Notional amount of foreign currency derivatives	$270.90	$282
Cash flow hedges [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Notional amount of foreign currency derivatives	117.1	137.6
Non-designated derivatives [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Notional amount of foreign currency derivatives	$153.80	$144.40

Derivative_Instruments_Cash_Fl

Derivative Instruments, Cash Flow Hedges and Offsetting of Derivatives (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Derivatives, Fair Value [Line Items]	'	'
Maximum length of time hedged in cash flow hedge	'1 year	'
Foreign exchange contract [Member] | Cash flow hedging [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative instruments, gain (loss) recognized in other comprehensive income (loss), Effective portion	$2.70	($2.10)
Operating expense [Member] | Foreign exchange contract [Member] | Cash flow hedging [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative instruments, gain (loss) reclassified from accumulated OCI into operating expense, Effective portion	$1	$1.40

Derivative_Instruments_NonDesi

Derivative Instruments, Non-Designated Hedges (Details) (Foreign exchange contract [Member], USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Maturity period of non designated hedges derivatives	'2 months	'
Other income (expense), net [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Derivative instruments not designated as hedging instruments, net loss	$0.60	$0.70

Goodwill_and_Purchased_Intangi2

Goodwill and Purchased Intangible Assets, Goodwill (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014
Goodwill [Roll Forward]	'
Balance as of December 31, 2013	$4,057.70
Additions due to business combinations	13.6
Balance as of March 31, 2014	$4,071.30

Goodwill_and_Purchased_Intangi3

Goodwill and Purchased Intangible Assets, Purchased Intangible Assets (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Purchased Intangible Assets [Line Items]	'	'
Finite-lived intangible assets, net	$115.10	'
Total purchased intangible assets, gross	673.5	655.7
Total purchased intangible assets, accumulated amortization	-525.7	-516.1
Total purchased intangible assets, impairments and other charges	-32.7	-32.7
Total purchased intangible assets, net	115.1	106.9
Technologies and patents [Member]	'	'
Purchased Intangible Assets [Line Items]	'	'
Finite-lived intangible assets, gross	592.1	581.4
Finite-lived intangible assets, accumulated amortization	-461.9	-453.4
Finite-lived intangible assets, impairments and other charges	-30.5	-30.5
Finite-lived intangible assets, net	99.7	97.5
Customer contracts, support agreements, and related relationships [Member]	'	'
Purchased Intangible Assets [Line Items]	'	'
Finite-lived intangible assets, gross	80.3	74.3
Finite-lived intangible assets, accumulated amortization	-63.7	-62.7
Finite-lived intangible assets, impairments and other charges	-2.2	-2.2
Finite-lived intangible assets, net	14.4	9.4
Other intangible assets [Member]	'	'
Purchased Intangible Assets [Line Items]	'	'
Finite-lived intangible assets, gross	1.1	'
Finite-lived intangible assets, accumulated amortization	-0.1	'
Finite-lived intangible assets, impairments and other charges	0	'
Finite-lived intangible assets, net	$1	'

Goodwill_and_Purchased_Intangi4

Goodwill and Purchased Intangible Assets, Finite Lived Intangible Assets by Class (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Amortization of intangible assets	$9.50	$7.50
Cost of Revenues [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Amortization of intangible assets	8.2	6.3
Sales and Marketing Expense [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Amortization of intangible assets	1	0.9
General and Administrative Expense [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Amortization of intangible assets	0.3	0.3
Operating expense [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Amortization of intangible assets	$1.30	$1.20

Goodwill_and_Purchased_Intangi5

Goodwill and Purchased Intangible Assets, Estimated Future Amortization Expense Intangible Assets (Details) (USD $)	Mar. 31, 2014
In Millions, unless otherwise specified
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]	'
Remainder of 2014	$29.30
2015	35.3
2016	21.1
2017	13
2018	6.1
Thereafter	10.3
Finite-lived intangible assets, net	$115.10

Other_Financial_Information_In

Other Financial Information, Inventories, Net (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014
In Millions, unless otherwise specified			Restructuring Plan 2014 [Member]
Inventory, Net [Abstract]	'	'	'
Production materials	$53.50	$51.30	'
Finished goods	1.2	1.4	'
Inventories	54.7	52.7	'
Inventory write-down	'	'	$8.40

Other_Financial_Information_Ot

Other Financial Information, Other Long Term Assets (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Other Long-term Assets [Abstract]	'	'
Cost method investments	$58.70	$57.20
Licensed software	9.5	90.4
Federal income tax receivable	20	20
Financed customer receivable	20.9	19.9
Inventory	14.9	15.2
Prepaid costs, deposits, and other	34.9	31.1
Other long-term assets	158.9	233.8
Restructuring charges	29.3	'
Asset impairment and write-downs [Member] | Restructuring Plan 2014 [Member]	'	'
Other Long-term Assets [Abstract]	'	'
Restructuring charges	$84.70	'

Other_Financial_Information_Wa

Other Financial Information, Warranties (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014
Movement in Standard Product Warranty Accrual [Roll Forward]	'
Balance as of December 31, 2013	$28
Provisions made during the period, net	7.3
Adjustments related to pre-existing warranties	0
Actual costs incurred during the period	-6.9
Balance as of March 31, 2014	$28.40

Other_Financial_Information_De

Other Financial Information, Deferred Revenue (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Deferred product revenue:	'	'
Total deferred revenue	$1,154.20	$1,069.30
Reported as:	'	'
Current	772.5	705.8
Long-term	381.7	363.5
Total deferred revenue	1,154.20	1,069.30
Sales Revenue, Product, Net [Member]	'	'
Deferred product revenue:	'	'
Undelivered product commitments and other product deferrals	186.3	184.9
Distributor inventory and other sell-through items	93.8	118.7
Deferred gross product revenue	280.1	303.6
Deferred cost of product revenue	-48.9	-58.6
Total deferred revenue	231.2	245
Reported as:	'	'
Total deferred revenue	231.2	245
Sales Revenue, Service, Net [Member]	'	'
Deferred product revenue:	'	'
Total deferred revenue	923	824.3
Reported as:	'	'
Total deferred revenue	$923	$824.30

Other_Financial_Information_Ot1

Other Financial Information, Other Expense, Net (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Other Income (Expenses), Net [Abstract]	'	'
Interest income	$2.10	$2.10
Interest expense	-15.4	-14.3
Other	167.5	2.1
Other income (expense), net	154.2	-10.1
Publicly-traded equity and privately-held investments, net realized gain	164	'
Privately-held investments, net gain	'	$1.60

Restructuring_and_Other_Charge2

Restructuring and Other Charges (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Restructuring Reserve [Line Items]	'	'
Restructuring and other charges	$122.40	$7.70
Restructuring Reserve [Roll Forward]	'	'
31-Dec-13	17.8	'
Charges	29.3	'
Cash Payments	-11.6	'
Non-cash Settlements and Other	-1.4	'
31-Mar-14	34.1	'
Cost of Revenues [Member]	'	'
Restructuring Reserve [Line Items]	'	'
Restructuring and other charges	8.4	0.7
Operating expense [Member]	'	'
Restructuring Reserve [Line Items]	'	'
Restructuring and other charges	114	7
Severance [Member]	'	'
Restructuring Reserve [Line Items]	'	'
Restructuring and other charges	28.3	4.4
Restructuring Reserve [Roll Forward]	'	'
31-Dec-13	5.6	'
Charges	28.3	'
Cash Payments	-3.7	'
Non-cash Settlements and Other	-0.6	'
31-Mar-14	29.6	'
Facilities [Member]	'	'
Restructuring Reserve [Line Items]	'	'
Restructuring and other charges	0.2	2.6
Restructuring Reserve [Roll Forward]	'	'
31-Dec-13	5.1	'
Charges	0.2	'
Cash Payments	-0.9	'
Non-cash Settlements and Other	0	'
31-Mar-14	4.4	'
Contract termination [Member]	'	'
Restructuring Reserve [Line Items]	'	'
Restructuring and other charges	0.8	0.7
Restructuring Reserve [Roll Forward]	'	'
31-Dec-13	7.1	'
Charges	0.8	'
Cash Payments	-7	'
Non-cash Settlements and Other	-0.8	'
31-Mar-14	0.1	'
Asset impairment and write-downs [Member]	'	'
Restructuring Reserve [Line Items]	'	'
Restructuring and other charges	93.1	0
Restructuring Plan 2014 [Member]	'	'
Restructuring Reserve [Roll Forward]	'	'
Inventory write-down	8.4	'
Restructuring Plan 2014 [Member] | Severance [Member]	'	'
Restructuring Reserve [Roll Forward]	'	'
Charges	28	'
Restructuring Plan 2014 [Member] | Contract termination [Member]	'	'
Restructuring Reserve [Roll Forward]	'	'
Charges	0.8	'
Restructuring Plan 2014 [Member] | Asset impairment and write-downs [Member]	'	'
Restructuring Reserve [Roll Forward]	'	'
Charges	84.7	'
Other Plans [Member]	'	'
Restructuring Reserve [Roll Forward]	'	'
Aggregate future restructuring charges expected	2.5	'
Minimum [Member] | Restructuring Plan 2014 [Member]	'	'
Restructuring Reserve [Roll Forward]	'	'
Aggregate future restructuring charges expected	60	'
Minimum [Member] | Restructuring Plan 2014 [Member] | Severance [Member]	'	'
Restructuring Reserve [Roll Forward]	'	'
Aggregate future restructuring charges expected	9	'
Minimum [Member] | Restructuring Plan 2014 [Member] | Facilities [Member]	'	'
Restructuring Reserve [Roll Forward]	'	'
Aggregate future restructuring charges expected	45	'
Minimum [Member] | Restructuring Plan 2014 [Member] | Asset impairment and write-downs [Member]	'	'
Restructuring Reserve [Roll Forward]	'	'
Aggregate future restructuring charges expected	6	'
Maximum [Member] | Restructuring Plan 2014 [Member]	'	'
Restructuring Reserve [Roll Forward]	'	'
Aggregate future restructuring charges expected	90	'
Maximum [Member] | Restructuring Plan 2014 [Member] | Severance [Member]	'	'
Restructuring Reserve [Roll Forward]	'	'
Aggregate future restructuring charges expected	11	'
Maximum [Member] | Restructuring Plan 2014 [Member] | Facilities [Member]	'	'
Restructuring Reserve [Roll Forward]	'	'
Aggregate future restructuring charges expected	55	'
Maximum [Member] | Restructuring Plan 2014 [Member] | Contract termination [Member]	'	'
Restructuring Reserve [Roll Forward]	'	'
Aggregate future restructuring charges expected	12	'
Maximum [Member] | Restructuring Plan 2014 [Member] | Asset impairment and write-downs [Member]	'	'
Restructuring Reserve [Roll Forward]	'	'
Aggregate future restructuring charges expected	$12	'

LongTerm_Debt_and_Financing_De

Long-Term Debt and Financing (Details) (USD $)	1 Months Ended	3 Months Ended
	Feb. 28, 2014	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Long-Term Debt [Line Items]	'	'	'	'
Long-term debt, gross	'	$1,350,000,000	'	'
Unaccreted discount	'	-1,100,000	'	'
Long-term debt	'	1,348,900,000	'	999,300,000
Change of control repurchase price percentage	101.00%	'	'	'
Financing Arrangements [Abstract]	'	'	'	'
Number of days due from receivable	'	'30 days	'	'
Sale of receivable	'	133,000,000	181,000,000	'
Proceeds from sale and collection of receivables	'	192,300,000	162,700,000	'
Receivables from sale of receivables	'	127,900,000	'	189,800,000
Cash received from financing provider that has not been recognized as revenue	'	61,500,000	'	62,300,000
Financing guarantee with recourse [Member]	'	'	'	'
Financing Arrangements [Abstract]	'	'	'	'
Guarantor obligations, current carrying value	'	21,900,000	'	'
Maximum [Member]	'	'	'	'
Financing Arrangements [Abstract]	'	'	'	'
Maximum term for guarantees related to third-party financing arrangements	'	'4 years	'	'
Fixed rate note due 2016 [Member]	'	'	'	'
Long-Term Debt [Line Items]	'	'	'	'
Long-term debt, gross	'	300,000,000	'	'
Long-term debt, effective interest rate	'	3.25%	'	'
Long-term debt, stated interest rate	'	3.10%	'	'
Fixed rate note due 2021 [Member]	'	'	'	'
Long-Term Debt [Line Items]	'	'	'	'
Long-term debt, gross	'	300,000,000	'	'
Long-term debt, effective interest rate	'	4.69%	'	'
Long-term debt, stated interest rate	'	4.60%	'	'
Fixed Rate Note Due 2024 [Member]	'	'	'	'
Long-Term Debt [Line Items]	'	'	'	'
Long-term debt, gross	'	350,000,000	'	'
Long-term debt, effective interest rate	'	4.63%	'	'
Long-term debt, stated interest rate	'	4.50%	'	'
Fixed rate note due 2041 [Member]	'	'	'	'
Long-Term Debt [Line Items]	'	'	'	'
Long-term debt, gross	'	$400,000,000	'	'
Long-term debt, effective interest rate	'	6.03%	'	'
Long-term debt, stated interest rate	'	5.95%	'	'

Equity_Stock_Repurchase_Activi

Equity, Stock Repurchase Activities (Details) (USD $)	1 Months Ended	3 Months Ended		1 Months Ended	3 Months Ended	1 Months Ended
Share data in Millions, except Per Share data, unless otherwise specified	Feb. 28, 2014	Mar. 31, 2014	Mar. 31, 2013	Feb. 28, 2014	Mar. 31, 2014	Jul. 31, 2013
				2014 Stock Repurchase Program [Member]	2014 Stock Repurchase Program [Member]	2013 Stock Repurchase Program [Member]
					institution
					agreement
Accelerated Share Repurchases [Line Items]	'	'	'	'	'	'
Stock repurchase program, authorized amount	$2,000,000,000	'	'	$1,200,000,000	'	$1,000,000,000
Number of accelerated share repurchase agreements entered into during period	'	'	'	'	2	'
Number of financial institutions participating in accelerated share repurchase program	'	'	'	'	2	'
Accelerated share repurchases, aggregate payments made during period	'	'	'	'	1,200,000,000	'
Stock repurchased and retired during period, shares	'	'	6.2	'	33.3	'
Common stock repurchased and retired under stock repurchase program, value	'	900,000,000	129,900,000	'	'	'
Accelerated share repurchases, remaining amount recorded in equity	'	'	'	'	300,000,000	'
Stock repurchase program, remaining authorized repurchase amount	'	'	'	'	$800,000,000	'
Common stock repurchased under stock repurchase program average purchase price (in dollars per share)	'	'	$20.99	'	'	'

Equity_Components_of_Accumulat

Equity, Components of Accumulated Other Comprehensive (Loss) Income, Net of Tax (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013
Accumulated Other Comprehensive (Loss) Income, Net of Tax [Roll Forward]	'		'
Balance as of December 31, 2013	$64.60		'
Other comprehensive gain before reclassifications	41.9		'
Amount reclassified from accumulated other comprehensive income	-104.6		'
Other comprehensive loss, net of tax	-62.7		-9.9
Balance as of March 31, 2014	1.9		'
Other income (expense), net	154.2		-10.1
Cost of revenues	450		388.4
Sales and marketing	273.4		256.1
General and administrative	74.9		58.5
Research and development	264		262.2
Unrealized Gains (Losses) on Available-for- Sale Securities	'		'
Accumulated Other Comprehensive (Loss) Income, Net of Tax [Roll Forward]	'		'
Balance as of December 31, 2013	66.2	[1]	'
Other comprehensive gain before reclassifications	38.1	[1]	'
Amount reclassified from accumulated other comprehensive income	-103.5	[1]	'
Other comprehensive loss, net of tax	-65.4	[1]	'
Balance as of March 31, 2014	0.8	[1]	'
Unrealized Gains (Losses) on Cash Flow Hedges	'		'
Accumulated Other Comprehensive (Loss) Income, Net of Tax [Roll Forward]	'		'
Balance as of December 31, 2013	2.2	[2]	'
Other comprehensive gain before reclassifications	2.1	[2]	'
Amount reclassified from accumulated other comprehensive income	-1.1	[2]	'
Other comprehensive loss, net of tax	1	[2]	'
Balance as of March 31, 2014	3.2	[2]	'
Cost of revenues	0.2		'
Sales and marketing	1.1		'
General and administrative	0.1		'
Research and development	0.3		'
Foreign Currency Translation Adjustments	'		'
Accumulated Other Comprehensive (Loss) Income, Net of Tax [Roll Forward]	'		'
Balance as of December 31, 2013	-3.8		'
Other comprehensive gain before reclassifications	1.7	[3]	'
Amount reclassified from accumulated other comprehensive income	0		'
Other comprehensive loss, net of tax	1.7		'
Balance as of March 31, 2014	($2.10)		'
[1]	The reclassifications out of accumulated other comprehensive income during the three months ended MarchB 31, 2014 for realized gains on available-for-sale securities of $103.5 million are included in other income (expense), net, in the Condensed Consolidated Statements of Operations.
[2]	The reclassifications out of accumulated other comprehensive income during the three months ended MarchB 31, 2014 for realized gains on cash flow hedges are included within cost of revenues of $0.2 million, sales and marketing of $1.1 million, and general and administrative of $0.1 million and for realized losses of $0.3 million within research and development for which the hedged transactions relate in the Condensed Consolidated Statements of Operations.
[3]	Taxes related to available-for-sale securities and cash flow hedges were not material for 2013.

Employee_Benefit_Plans_Details

Employee Benefit Plans (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Share-Based Compensation Plans	'	'
Common stock, shares, issued	473,400,000	495,200,000
Outstanding stock options, restricted stock units, and restricted stock awards from awards assumed	5,700,000	'
Number of Shares	'	'
Balance as of December 31, 2013 (in shares)	23,100,000	'
Canceled (in shares)	-300,000	'
Exercised (in shares)	-3,700,000	'
Expired (in shares)	-600,000	'
Balance as of March 31, 2014 (in shares)	18,500,000	'
Weighted Average Exercise Price per Share	'	'
Balance as of December 31, 2013 (in dollars per share)	$25.15	'
Canceled (in dollars per share)	$30.34	'
Exercised (in dollars per share)	$20.24	'
Expired (in dollars per share)	$28.76	'
Balance as of March 31, 2014 (in dollars per share)	$25.92	'
Weighted average remaining contractual term at March 31, 2014	'2 years 2 months 12 days	'
Aggregate intrinsic value at March 31, 2014	$52,900,000	'
Vested or expected-to-vest options at March 31, 2014 (in shares)	18,200,000	'
Vested or expected-to-vest options, weighted average exercise price at March 31, 2014 (in dollars per share)	$26.04	'
Vested and expected-to-vest options, weighted average remaining contractual term at March 31, 2014	'2 years 1 month 6 days	'
Vested or expected-to-vest options, aggregate intrinsic value at March 31, 2014	50,100,000	'
Exercisable options at March 31, 2014 (in shares)	16,700,000	'
Exercisable options, weighted average exercise price at March 31, 2014 (in dollars per share)	$26.48	'
Exercisable options, weighted average remaining contractual term at March 31, 2014	'1 year 9 months 18 days	'
Exercisable options, aggregate intrinsic value at March 31, 2014	36,300,000	'
Share price (in dollars per share)	$25.76	'
Pre-tax intrinsic value of options exercised	23,800,000	'
Equity incentive plan 2006	'	'
Share-Based Compensation Plans	'	'
Number of shares in authorized	149,500,000	'
Number of shares available for future issuance	49,800,000	'
Plan 1996 and 2000 [Member]	'	'
Share-Based Compensation Plans	'	'
Maximum additional shares expire unexercised, under 1996 and 2000 plan	75,000,000	'
Equity Incentive Plan 1996, 2000, and 2006 [Member]	'	'
Share-Based Compensation Plans	'	'
Number of shares outstanding	33,900,000	'
Employee stock purchase plan 2008 [Member]	'	'
Share-Based Compensation Plans	'	'
Number of shares available for future issuance	4,600,000	'
Common stock, capital shares reserved for future issuance	19,000,000	'
Share-based compensation arrangement by share-based payment award, discount from market price	15.00%	'
Periodic payroll deduction - percentage of base salary	10.00%	'
Maximum purchase of common stock, shares	6,000	'
Share-based compensation arrangement by share-based payment award, offering period	'12 months	'
Maximum purchase of common stock, value	$25,000	'
Share-based compensation arrangement by share-based payment award, expiration period	'1 year	'
Common stock, shares, issued	14,400,000	'

Employee_Benefit_Plans_Share_B

Employee Benefit Plans, Share Based Compensation, Equity Instruments Other Than Options (Details) (USD $)	0 Months Ended	3 Months Ended
In Millions, except Share data, unless otherwise specified	Feb. 20, 2014	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014		Mar. 31, 2014		Mar. 31, 2014		Mar. 31, 2014
			Employee stock purchase plan 2008 [Member]	Employee stock purchase plan 2008 [Member]	Restricted stock units (RSUs)		Performance shares (PSAs)		Restricted stock awards (RSAs)		RSUs, RSAs, and PSAs [Member]
Number of Shares	'	'	'	'	'		'		'		'
Balance as of December 31, 2013 (in shares)	'	'	'	'	'		'		'		25,400,000
Granted (in shares)	'	'	'	'	1,900,000	[1],[2]	800,000	[1],[3]	'		'
Assumed (in shares)	'	'	'	'	400,000	[4]	200,000	[4]	900,000	[4]	'
Vested (in shares)	'	-1,000,000	'	'	-4,600,000		'		-300,000		'
Canceled (in shares)	'	'	'	'	-500,000		-2,100,000		'		'
Balance as of March 31, 2014 (in shares)	'	'	'	'	'		'		'		21,100,000
Weighted Average Grant-Date Fair Value per Share	'	'	'	'	'		'		'		'
Balance as of December 31, 2013 (in dollars per share)	'	'	'	'	'		'		'		$23.44
Granted (in dollars per share)	'	'	'	'	$22.14	[1],[2]	$25.22	[1],[3]	'		'
Assumed (in dollars per share)	'	'	'	'	$22.66	[4]	$22.66	[4]	$22.66	[4]	'
Vested (in dollars per share)	'	'	'	'	$24.05		$38.10		$19.59		'
Canceled (in dollars per share)	'	'	'	'	$21.55		$33.85		'		'
Balance as of March 31, 2014 (in dollars per share)	'	'	'	'	'		'		'		$21.57
Weighted Average Remaining Contractual Term (In Years)	'	'	'	'	'		'		'		'1 year 4 months 24 days
Aggregate Intrinsic Value	'	'	'	'	'		'		'		$543.30
Aggregate number of shares subject to PSAs granted	'	'	'	'	'		400,000		'		'
Minimum shares to be issued on achievement of performance goals in respect of PSAs	'	'	'	'	'		0		'		'
Maximum shares to be issued on achievement of performance goals in respect of PSAs	'	'	'	'	'		800,000		'		'
Intended quarterly cash dividend based on most recent announcement (in dollars per share)	$0.10	'	'	'	'		'		'		'
Employee Stock Purchase Plan	'	'	'	'	'		'		'		'
Employee stock purchase plans offering period duration	'	'	'6 months	'	'		'		'		'
Stock issued during period, shares, employee stock purchase plans	'	'	1,500,000	1,900,000	'		'		'		'
Average price of common stock, per share	'	'	$18.67	$15.05	'		'		'		'
[1]	On February 20, 2014, the Company announced its intention to initiate a quarterly cash dividend of $0.10 per share of common stock in the third quarter of 2014. As a result of the Company's announcement, the grant date fair value of RSUs and PSAs granted after the announcement date were reduced by the present value of the dividends expected to be paid on the underlying shares of common stock during the requisite and derived service period as these awards are not entitled to receive dividends until vested.
[2]	Includes service-based and market-based RSUs granted under the 2006 Plan according to its terms.
[3]	The number of shares subject to PSAs granted represents the aggregate maximum number of shares that may be issued pursuant to the award over its full term. The aggregate number of shares subject to these PSAs that would be issued if performance goals determined by the Compensation Committee are achieved at target is 0.4 million shares. Depending on achievement of such performance goals, the range of shares that could be issued under these awards is 0 to 0.8 million shares.
[4]	RSUs, RSAs, and PSAs assumed in connection with the acquisition of WANDL.

Employee_Benefit_Plans_Assumpt

Employee Benefit Plans, Assumptions and Resulting Estimates of Fair Value (Details) (USD $)	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
ESPP [Member]	'		'
Estimates of Fair Value	'		'
Volatility	33.00%	[1]	36.00%	[1]
Risk-free interest rate	0.10%	[1]	0.10%	[1]
Expected life (years)	'6 months	[1]	'6 months	[1]
Dividend yield	0.00%	[1]	0.00%	[1]
Weighted-average fair value per share (in dollars per share)	$6.37	[1]	$5.63	[1]
Market-based RSUs [Member]	'		'
Estimates of Fair Value	'		'
Volatility	36.00%	[2]	'
Risk-free interest rate	1.60%	[2]	'
Weighted-average fair value per share, RSUs (in dollars per share)	$18.28	[2]	'
Market-based RSUs [Member] | Minimum [Member]	'		'
Estimates of Fair Value	'		'
Dividend yield	0.00%	[2]	'
Market-based RSUs [Member] | Maximum [Member]	'		'
Estimates of Fair Value	'		'
Dividend yield	1.50%	[2]	'
[1]	The Black-Scholes-Merton option-pricing model is utilized to estimate the fair value of ESPP.
[2]	The fair value of market-based RSUs utilizes a Monte Carlo valuation methodology. The Company amortizes the fair value of these awards over the derived service period adjusted for estimated forfeitures for each separately vesting tranche of the award. Provided that the derived service is rendered, the total fair value of the market-based RSUs at the date of grant is recognized as compensation expense even if the market condition is not achieved. However, the number of shares that ultimately vest can vary significantly with the performance of the specified market criteria.

Employee_Benefit_Plans_Share_B1

Employee Benefit Plans, Share Based Compensation by Cost and Expense Categories (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Stock Based Compensation Expense Recorded in Cost and Expense Categories	'	'
Share-based compensation expense	$60.80	$49.90
Stock Options [Member]	'	'
Stock Based Compensation Expense Recorded in Cost and Expense Categories	'	'
Share-based compensation expense	5.1	9.5
RSUs, RSAs, and PSAs [Member]	'	'
Stock Based Compensation Expense Recorded in Cost and Expense Categories	'	'
Share-based compensation expense	51.8	37
ESPP [Member]	'	'
Stock Based Compensation Expense Recorded in Cost and Expense Categories	'	'
Share-based compensation expense	3.9	3.4
Cost of Revenues, Product [Member]	'	'
Stock Based Compensation Expense Recorded in Cost and Expense Categories	'	'
Share-based compensation expense	1.3	0.9
Cost of Revenues, Service [Member]	'	'
Stock Based Compensation Expense Recorded in Cost and Expense Categories	'	'
Share-based compensation expense	4	4.6
Research and Development [Member]	'	'
Stock Based Compensation Expense Recorded in Cost and Expense Categories	'	'
Share-based compensation expense	32.1	23.6
Sales and Marketing [Member]	'	'
Stock Based Compensation Expense Recorded in Cost and Expense Categories	'	'
Share-based compensation expense	14.6	14.5
General and Administrative [Member]	'	'
Stock Based Compensation Expense Recorded in Cost and Expense Categories	'	'
Share-based compensation expense	$8.80	$6.30

Employee_Benefit_Plans_Share_B2

Employee Benefit Plans, Share Based Compensation by Share Based Payment Award Types (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014
Stock Options [Member]	'
Unrecognized Compensation Cost [Abstract]	'
Unrecognized Compensation Cost	$25.90
Weighted Average Period (In Years)	'1 year 8 months 12 days
RSUs, RSAs, and PSAs [Member]	'
Unrecognized Compensation Cost [Abstract]	'
Unrecognized Compensation Cost	$293.10
Weighted Average Period (In Years)	'2 years

Segments_Details

Segments (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]	'	'
Total net revenues	$1,170.10	$1,059.20
Routing [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Total net revenues	549.8	513.6
Switching [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Total net revenues	192	131.5
Security [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Total net revenues	134.2	136.7
Total product [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Total net revenues	876	781.8
Total service [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Total net revenues	$294.10	$277.40

Segments_Geographical_Details

Segments, Geographical (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Net Revenues by Geographic Region [Line Items]	'	'	'
Total net revenues	$1,170.10	$1,059.20	'
Property and equipment, net	905.7	'	882.3
United States [Member]	'	'	'
Net Revenues by Geographic Region [Line Items]	'	'	'
Total net revenues	623.7	547	'
Property and equipment, net	823	'	801.3
Other [Member]	'	'	'
Net Revenues by Geographic Region [Line Items]	'	'	'
Total net revenues	57.8	45.1	'
Americas [Member]	'	'	'
Net Revenues by Geographic Region [Line Items]	'	'	'
Total net revenues	681.5	592.1	'
EMEA [Member]	'	'	'
Net Revenues by Geographic Region [Line Items]	'	'	'
Total net revenues	295.7	290.6	'
Asia Pacific [Member]	'	'	'
Net Revenues by Geographic Region [Line Items]	'	'	'
Total net revenues	192.9	176.5	'
International [Member]	'	'	'
Net Revenues by Geographic Region [Line Items]	'	'	'
Property and equipment, net	$82.70	'	$81

Segments_Major_Customers_Detai

Segments, Major Customers (Details) (Sales revenue, segment [Member], Customer concentration risk [Member])	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
	AT&T [Member]	Verizon [Member]
Concentration Risk [Line Items]	'	'
Concentration risk, percentage	10.20%	10.10%

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2009	Mar. 31, 2014
			Foreign country	Maximum [Member]
Income Tax Contingency [Line Items]	'	'	'	'
Tax on gain of equity investments, net of valuation allowance release of $24.7	$35.60	$0	'	'
Benefit from restructuring costs	-30.8	0	'	'
Tax settlement with Internal Revenue Service (bIRSb)	0	-27.8	'	'
Reinstatement of the U.S. federal R&D tax credit	0	-15.2	'	'
Effective income tax rate reconciliation, at federal statutory income tax rate	25.30%	-18.30%	'	'
Federal statutory rate	35.00%	35.00%	'	'
Unrecognized tax benefits	142.9	'	'	'
Unrecognized tax benefits that would impact effective tax rate	131.9	'	'	'
Greater than remote likelihood decrease in gross unrecognized tax benefits within next 12 months	'	'	'	2.5
Interest and penalties recorded	'	'	4.6	'
Valuation allowance release related to gain on sale of equity investments	$24.70	'	'	'

Net_Income_per_Share_Details

Net Income per Share (Details) (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Numerator	'	'
Net income	$110.60	$91
Denominator	'	'
Weighted-average shares used to compute basic net income per share	486.2	504.7
Dilutive effect of employee stock awards (in shares)	10.3	8
Weighted-average shares used to compute diluted net income per share	496.5	512.7
Net income per share:	'	'
Basic (in dollars per share)	$0.23	$0.18
Diluted (in dollars per share)	$0.22	$0.18
Net Income per Share Textuals	'	'
Anti-dilutive shares excluded from computation of diluted earnings per share	25.4	24.7

Commitments_and_Contingencies_

Commitments and Contingencies (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Summarization of principal contractual obligations	'	'	'
Future minimum payments under the non-cancelable operating leases	$221,300,000	'	'
Rent expense	13,000,000	13,700,000	'
Total purchase commitments	489,700,000	'	'
Accrual for estimated carrying charges or obsolete materials charges	20,500,000	'	'
Long-term debt, carrying value	1,348,900,000	'	999,300,000
Long-term debt, gross	1,350,000,000	'	'
Indemnity-related and service-related escrows	71,600,000	'	'
Campus build out commitments	13,900,000	'	'
Other contractual obligations	7,800,000	'	'
Long-term income taxes payable	121,700,000	'	114,400,000
Fixed rate note due 2016 [Member]	'	'	'
Summarization of principal contractual obligations	'	'	'
Long-term debt, gross	300,000,000	'	'
Long-term debt, effective interest rate	3.25%	'	'
Long-term debt, stated interest rate	3.10%	'	'
Fixed rate note due 2021 [Member]	'	'	'
Summarization of principal contractual obligations	'	'	'
Long-term debt, gross	300,000,000	'	'
Long-term debt, effective interest rate	4.69%	'	'
Long-term debt, stated interest rate	4.60%	'	'
Fixed Rate Note Due 2024 [Member]	'	'	'
Summarization of principal contractual obligations	'	'	'
Long-term debt, gross	350,000,000	'	'
Long-term debt, effective interest rate	4.63%	'	'
Long-term debt, stated interest rate	4.50%	'	'
Fixed rate note due 2041 [Member]	'	'	'
Summarization of principal contractual obligations	'	'	'
Long-term debt, gross	$400,000,000	'	'
Long-term debt, effective interest rate	6.03%	'	'
Long-term debt, stated interest rate	5.95%	'	'

Commitments_and_Contingencies_1

Commitments and Contingencies, Guarantees (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Financing guarantees, bank guarantees, and standby letters of credit [Member]	'	'
Guarantor Obligations [Line Items]	'	'
Guarantor obligations, current carrying value	$28.70	$40.10
Financing guarantee with recourse [Member]	'	'
Guarantor Obligations [Line Items]	'	'
Guarantor obligations, current carrying value	$21.90	'