2.2.0.25truefalse0040 - Statement - CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITYtruefalseIn Millionsfalse1falsefalseUSDtruefalse{us-gaap_StatementEquityComponentsAxis} : Common Stock 1/1/2010 - 12/31/2010 D2010_CommonStockMemberhttp://www.sec.gov/CIK0001065865na0001-01-01T00:00:000001-01-01T00:00:00falsefalseus-gaap_CommonStockMemberus-gaap_StatementEquityComponentsAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_CommonStockMemberus-gaap_StatementEquityComponentsAxisexplicitMembersharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170$2falsefalseUSDtruefalse{us-gaap_StatementEquityComponentsAxis} : Retained Earnings 1/1/2010 - 12/31/2010 USD ($) $D2010_RetainedEarningsMemberhttp://www.sec.gov/CIK0001065865na0001-01-01T00:00:000001-01-01T00:00:00falsefalseus-gaap_RetainedEarningsMemberus-gaap_StatementEquityComponentsAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_RetainedEarningsMemberus-gaap_StatementEquityComponentsAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$3falsefalseUSDtruefalse{us-gaap_StatementEquityComponentsAxis} : Accumulated Other Comprehensive Income (Loss) 1/1/2010 - 12/31/2010 USD ($) $D2010_AccumulatedOtherComprehensiveIncomeMemberhttp://www.sec.gov/CIK0001065865na0001-01-01T00:00:000001-01-01T00:00:00falsefalseus-gaap_AccumulatedOtherComprehensiveIncomeMemberus-gaap_StatementEquityComponentsAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_AccumulatedOtherComprehensiveIncomeMemberus-gaap_StatementEquityComponentsAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$4falsefalseUSDtruefalse{us-gaap_StatementEquityComponentsAxis} : Nonredeemable Noncontrolling Interests in Subsidiary 1/1/2010 - 12/31/2010 USD ($) $D2010_NoncontrollingInterestMemberhttp://www.sec.gov/CIK0001065865na0001-01-01T00:00:000001-01-01T00:00:00falsefalseus-gaap_NoncontrollingInterestMemberus-gaap_StatementEquityComponentsAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_NoncontrollingInterestMemberus-gaap_StatementEquityComponentsAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$5falsefalseUSDtruefalse{us-gaap_StatementEquityComponentsAxis} : Comprehensive Income 1/1/2010 - 12/31/2010 USD ($) $D2010_ComprehensiveIncomeMemberhttp://www.sec.gov/CIK0001065865na0001-01-01T00:00:000001-01-01T00:00:00falsefalseus-gaap_ComprehensiveIncomeMemberus-gaap_StatementEquityComponentsAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ComprehensiveIncomeMemberus-gaap_StatementEquityComponentsAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$6falsefalseUSDfalsefalse1/1/2010 - 12/31/2010 USD ($) USD ($) / shares $D2010http://www.sec.gov/CIK0001065865na0001-01-01T00:00:000001-01-01T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0sharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0USDUSD$1false0us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestus-gaaptruecreditinstantNo definition available.falsefalsefalsetruefalsefalsefalsetruefalsefalseperiodstartlabelinstant2008-01-01T00:00:000001-01-01T00:00:001truefalsefalse17000001.7falsetruefalsetruefalse2truefalsefalse14803000001480.3falsetruefalsetruefalse3truefalsefalse48000004.8falsetruefalsetruefalse4truefalsefalse71000007.1falsetruefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse14939000001493.9falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryTotal of Stockholders' Equity (deficit) items, net of receivables from officers, directors owners, and affiliates of the entity including portions attributable to both the parent and noncontrolling interests (previously referred to as minority interest), if any. The entity including portions attributable to the parent and noncontrolling interests is sometimes referred to as the economic entity. This excludes temporary equity and is sometimes called permanent equity.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 25 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 26 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A3 -Appendix A falsefalseBalance at Dec. 31, 20072false0us-gaap_SharesIssuedus-gaaptruenainstantNo definition available.falsefalsefalsetruefalsefalsefalsetruefalsefalseperiodstartlabelinstant2008-01-01T00:00:000001-01-01T00:00:001truefalsefalse166300000166.3falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsefalsefalseSharesxbrli:sharesItemTypesharesNumber of shares of stock issued as of the balance sheet date, including shares that had been issued and were previously outstanding but which are now held in the treasury.No authoritative reference available.falsefalseBalance (in shares) at Dec. 31, 20073true0us-gaap_IncreaseDecreaseInStockholdersEquityRollForwardus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringA roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.falsefalseIncrease (Decrease) in Stockholders' Equity4false0jns_NetIncomeLossExcludingRedeemableNoncontrollingInterestsjnsfalsecreditdurationThe portion of consolidated profit or loss for the period, net of income taxes, which is attributable to the parent,...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2truefalsefalse136900000136.9falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4truefalsefalse24000002.4falsefalsefalsetruefalse5truefalsefalse139300000139.3falsefalsefalsetruefalse6truefalsefalse139300000139.3falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe portion of consolidated profit or loss for the period, net of income taxes, which is attributable to the parent, excluding the effect of redeemable noncontrolling interests.No authoritative reference available.falsefalseNet income (loss) attributable to JCG5false0us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTaxus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3truefalsefalse-3800000-3.8falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5truefalsefalse-3800000-3.8falsefalsefalsetruefalse6truefalsefalse-3800000-3.8falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryAppreciation or loss in value (before reclassification adjustment) of the total of unsold securities during the period being reported on, net of tax. Reclassification adjustments include: (1) the unrealized holding gain or loss, net of tax, at the date of the transfer for a debt security from the held-to-maturity category transferred into the available-for-sale category. Also includes the unrealized gain or loss at the date of transfer for a debt security from the available-for-sale category transferred into the held-to-maturity category; (2) the unrealized gains or losses realized upon the sale of securities, after tax; and (3) the unrealized gains or losses realized upon the write-down of securities, after tax.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 17, 22 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 13 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(3) Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 24 -Subparagraph b falsefalseNet unrealized gain (loss) on available-for-sale securities6false0us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecreaseus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3truefalsefalse5000000.5falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5truefalsefalse5000000.5falsefalsefalsetruefalse6truefalsefalse5000000.5falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryNet of tax effect change in accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges after taxes. A cash flow hedge is a hedge of the exposure to variability in the cash flows of a recognized asset or liability or a forecasted transaction that is attributable to a particular risk. The change includes an entity's share of an equity investee's increase (decrease) in deferred hedging gains or losses.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 14, 17, 20, 26 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 31, 46 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(3) Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 46 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 24 -Subparagraph b Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 14, 17, 20, 24, 26 falsefalseAmortization of net loss on cash flow hedge7false0us-gaap_OtherComprehensiveIncomeReclassificationAdjustmentForSaleOfSecuritiesIncludedInNetIncomeNetOfTaxus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3truefalsefalse-900000-0.9falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5truefalsefalse-900000-0.9falsefalsefalsetruefalse6truefalsefalse-900000-0.9falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryReclassification adjustment for unrealized gains or losses realized upon the sale of securities, after tax.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(3) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 24 -Subparagraph b Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 18, 19 falsefalseReclassification for net gains included in net income8false0us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPeriodIncreaseDecreaseus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3truefalsefalse-5900000-5.9falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5truefalsefalse-5900000-5.9falsefalsefalsetruefalse6truefalsefalse-5900000-5.9falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryAdjustment that results from the process of translating subsidiary financial statements and foreign equity investments into functional currency of the reporting entity, net of tax.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 52 -Paragraph 13, 20, 31 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(3) Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 24 -Subparagraph b Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 14, 17, 19, 26 falsefalseForeign currency translation adjustment9false0us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterestus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5truefalsefalse129200000129.2falsefalsefalsetruefalse6truefalsefalse129200000129.2falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the economic entity, including both controlling (parent) and noncontrolling interests. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, including any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A5 -Appendix A Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 29 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph a truefalseComprehensive income10false0jns_AdjustmentsToRetainedEarningsCapitalAmortizationOfShareBasedCompensationjnsfalsecreditdurationThis element represents the stock-based compensation cost which is based on the grant date fair value of awards expected to...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2truefalsefalse2930000029.3falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4truefalsefalse21000002.1falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse3140000031.4falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis element represents the stock-based compensation cost which is based on the grant date fair value of awards expected to vest at the end of the stated service period, comprised of the total value of the awards less an estimate for forfeitures. The grant date fair value of stock options is determined using the Black-Scholes option pricing model and the grant date fair value of restricted stock is determined from a quoted market price. The Black-Scholes model requires significant management estimates including volatility and expected life.No authoritative reference available.falsefalseAmortization of stock-based compensation11false0us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeituresus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse16000001.6falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsefalsefalseSharesxbrli:sharesItemTypesharesNumber of shares issued during the period related to Restricted Stock Awards, net of any shares forfeited.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 10 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 4, 5 falsefalseIssuance and forfeitures of restricted stock awards, net (in shares)12false0jns_AdjustmentsToRetainedEarningsCapitalTaxEffectFromShareBasedCompensationjnsfalsecreditdurationThis element represents the tax benefit associated with any share-based compensation plan other than an employee stock...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2truefalsefalse34000003.4falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse34000003.4falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis element represents the tax benefit associated with any share-based compensation plan other than an employee stock ownership plan (ESOP).No authoritative reference available.falsefalseTax impact of stock-based compensation13false0jns_StockOptionExercisesAndEmployeeStockPurchasesjnsfalsecreditdurationValue stock issued during the period as a result of the exercise of stock options and as a result of stock issued during the...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2truefalsefalse2160000021.6falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse2160000021.6falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryValue stock issued during the period as a result of the exercise of stock options and as a result of stock issued during the period for an employee stock purchase plan.No authoritative reference available.falsefalseStock option exercises and employee stock purchases14false0jns_StockOptionExercisesAndEmployeeStockPurchasesSharesjnsfalsenadurationNumber of shares issued during the period as a result of the exercise of stock options and purchases through an employee...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse11000001.1falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsefalsefalseSharesxbrli:sharesItemTypesharesNumber of shares issued during the period as a result of the exercise of stock options and purchases through an employee stock purchase plan.No authoritative reference available.falsefalseStock option exercises and employee stock purchases (in shares)15false0us-gaap_StockRepurchasedDuringPeriodValueus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse-100000-0.1falsefalsefalsetruefalse2truefalsefalse-291600000-291.6falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse-291700000-291.7falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis element represents the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30, 31 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 10 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 43 -Chapter 1 -Section B -Paragraph 11A falsefalseRepurchase of common stock16false0us-gaap_StockRepurchasedDuringPeriodSharesus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse-11100000-11.1falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsefalsefalseSharesxbrli:sharesItemTypesharesNumber of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 10 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 43 -Chapter 1 -Section B -Paragraph 11A falsefalseRepurchase of common stock (in shares)17false0jns_MinorityInterestInConsolidatedInvestmentProductsjnsfalsecreditdurationNoncontrolling interests that are not subject to put rights consist of third party investors in consolidated investment...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4truefalsefalse11000001.1falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse11000001.1falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryNoncontrolling interests that are not subject to put rights consist of third party investors in consolidated investment products, certain third party interests granted to employees, and undistributed earnings attributable to such interests. Certain of the third party interests granted to employees will become subject to put rights upon vesting.No authoritative reference available.falsefalseNoncontrolling interests in consolidated investment products18false0us-gaap_MinorityInterestDecreaseFromRedemptionsus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4truefalsefalse-300000-0.3falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse-300000-0.3falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryDecrease in noncontrolling interest as a result of redeeming or purchasing the interests of noncontrolling shareholders.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(2) falsefalsePurchase of noncontrolling interests19false0us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHoldersus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4truefalsefalse-2500000-2.5falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse-2500000-2.5falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryDecrease in noncontrolling interest balance from payment of dividends or other distributions to noncontrolling interest holders.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(2) falsefalseDistributions to noncontrolling interests20false0us-gaap_MinorityInterestChangeInRedemptionValueus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2truefalsefalse137200000137.2falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse137200000137.2falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryChange in noncontrolling interest during the period as a result of a change in the redemption value of redeemable noncontrolling interest.No authoritative reference available.falsefalseChange in value of redeemable noncontrolling interests21false0us-gaap_DividendsCommonStockCashus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1falsefalsefalse00falsefalsefalsetruefalse2truefalsefalse-6500000-6.5falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse-6500000-6.5falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryCommon stock cash dividend declared by an entity during the period. This element includes paid and unpaid dividends declared during the period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 falsefalseCommon stock dividends ($0.04 per share)22false0us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestus-gaaptruecreditinstantNo definition available.falsefalsefalsetruefalsefalsefalsefalsetruefalseperiodendlabelinstant2008-12-31T00:00:000001-01-01T00:00:001truefalsefalse16000001.6falsefalsefalsetruefalse2truefalsefalse15106000001510.6falsefalsefalsetruefalse3truefalsefalse-5300000-5.3falsefalsefalsetruefalse4truefalsefalse99000009.9falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse15168000001516.8falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryTotal of Stockholders' Equity (deficit) items, net of receivables from officers, directors owners, and affiliates of the entity including portions attributable to both the parent and noncontrolling interests (previously referred to as minority interest), if any. The entity including portions attributable to the parent and noncontrolling interests is sometimes referred to as the economic entity. This excludes temporary equity and is sometimes called permanent equity.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 25 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 26 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A3 -Appendix A falsefalseBalance at Dec. 31, 200823false0us-gaap_SharesIssuedus-gaaptruenainstantNo definition available.falsefalsefalsetruefalsefalsefalsefalsetruefalseperiodendlabelinstant2008-12-31T00:00:000001-01-01T00:00:001truefalsefalse157900000157.9falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsefalsefalseSharesxbrli:sharesItemTypesharesNumber of shares of stock issued as of the balance sheet date, including shares that had been issued and were previously outstanding but which are now held in the treasury.No authoritative reference available.falsefalseBalance (in shares) at Dec. 31, 200824true0us-gaap_IncreaseDecreaseInStockholdersEquityRollForwardus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringA roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.falsefalseIncrease (Decrease) in Stockholders' Equity25false0jns_NetIncomeLossExcludingRedeemableNoncontrollingInterestsjnsfalsecreditdurationThe portion of consolidated profit or loss for the period, net of income taxes, which is attributable to the parent,...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2truefalsefalse-757100000-757.1falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4truefalsefalse30000003.0falsefalsefalsetruefalse5truefalsefalse-754100000-754.1falsefalsefalsetruefalse6truefalsefalse-754100000-754.1falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe portion of consolidated profit or loss for the period, net of income taxes, which is attributable to the parent, excluding the effect of redeemable noncontrolling interests.No authoritative reference available.falsefalseNet income (loss) attributable to JCG26false0us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTaxus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3truefalsefalse24000002.4falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5truefalsefalse24000002.4falsefalsefalsetruefalse6truefalsefalse24000002.4falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryAppreciation or loss in value (before reclassification adjustment) of the total of unsold securities during the period being reported on, net of tax. Reclassification adjustments include: (1) the unrealized holding gain or loss, net of tax, at the date of the transfer for a debt security from the held-to-maturity category transferred into the available-for-sale category. Also includes the unrealized gain or loss at the date of transfer for a debt security from the available-for-sale category transferred into the held-to-maturity category; (2) the unrealized gains or losses realized upon the sale of securities, after tax; and (3) the unrealized gains or losses realized upon the write-down of securities, after tax.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 17, 22 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 13 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(3) Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 24 -Subparagraph b falsefalseNet unrealized gain (loss) on available-for-sale securities27false0us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecreaseus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3truefalsefalse12000001.2falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5truefalsefalse12000001.2falsefalsefalsetruefalse6truefalsefalse12000001.2falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryNet of tax effect change in accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges after taxes. A cash flow hedge is a hedge of the exposure to variability in the cash flows of a recognized asset or liability or a forecasted transaction that is attributable to a particular risk. The change includes an entity's share of an equity investee's increase (decrease) in deferred hedging gains or losses.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 14, 17, 20, 26 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 31, 46 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(3) Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 46 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 24 -Subparagraph b Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 14, 17, 20, 24, 26 falsefalseAmortization of net loss on cash flow hedge28false0us-gaap_OtherComprehensiveIncomeReclassificationAdjustmentForSaleOfSecuritiesIncludedInNetIncomeNetOfTaxus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3truefalsefalse-400000-0.4falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5truefalsefalse-400000-0.4falsefalsefalsetruefalse6truefalsefalse-400000-0.4falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryReclassification adjustment for unrealized gains or losses realized upon the sale of securities, after tax.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(3) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 24 -Subparagraph b Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 18, 19 falsefalseReclassification for net gains included in net income29false0us-gaap_OtherComprehensiveIncomeReclassificationAdjustmentForWriteDownOfSecuritiesIncludedInNetIncomeNetOfTaxus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3truefalsefalse33000003.3falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5truefalsefalse33000003.3falsefalsefalsetruefalse6truefalsefalse33000003.3falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryReclassification adjustment for unrealized gains or losses realized upon the write-down of securities, after tax.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(3) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 24 -Subparagraph b Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 18, 19, 22 falsefalseImpairment of available-for-sale securities30false0us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPeriodIncreaseDecreaseus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3truefalsefalse-200000-0.2falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5truefalsefalse-200000-0.2falsefalsefalsetruefalse6truefalsefalse-200000-0.2falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryAdjustment that results from the process of translating subsidiary financial statements and foreign equity investments into functional currency of the reporting entity, net of tax.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 52 -Paragraph 13, 20, 31 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(3) Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 24 -Subparagraph b Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 14, 17, 19, 26 falsefalseForeign currency translation adjustment31false0us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterestus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5truefalsefalse-747800000-747.8falsefalsefalsetruefalse6truefalsefalse-747800000-747.8falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the economic entity, including both controlling (parent) and noncontrolling interests. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, including any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A5 -Appendix A Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 29 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph a truefalseComprehensive income32false0us-gaap_StockIssuedDuringPeriodValueNewIssuesus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse2000000.2falsefalsefalsetruefalse2truefalsefalse217900000217.9falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse218100000218.1falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryValue of new stock issued during the period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 10 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30, 31 -Article 5 falsefalseCommon stock issuance33false0us-gaap_StockIssuedDuringPeriodSharesNewIssuesus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse2090000020.9falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsefalsefalseSharesxbrli:sharesItemTypesharesNumber of new stock issued during the period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 10 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30 -Article 5 falsefalseCommon stock issuance (in shares)34false0jns_IssuanceOfConvertibleDebtjnsfalsecreditdurationThe amount of convertible debt issued during the period. The convertible debts are convertible under certain circumstances...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2truefalsefalse2640000026.4falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse2640000026.4falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe amount of convertible debt issued during the period. The convertible debts are convertible under certain circumstances into cash.No authoritative reference available.falsefalseConvertible debt issuance35false0jns_AdjustmentsToRetainedEarningsCapitalAmortizationOfShareBasedCompensationjnsfalsecreditdurationThis element represents the stock-based compensation cost which is based on the grant date fair value of awards expected to...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2truefalsefalse3470000034.7falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4truefalsefalse40000004.0falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse3870000038.7falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis element represents the stock-based compensation cost which is based on the grant date fair value of awards expected to vest at the end of the stated service period, comprised of the total value of the awards less an estimate for forfeitures. The grant date fair value of stock options is determined using the Black-Scholes option pricing model and the grant date fair value of restricted stock is determined from a quoted market price. The Black-Scholes model requires significant management estimates including volatility and expected life.No authoritative reference available.falsefalseAmortization of stock-based compensation36false0us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeituresus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse32000003.2falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsefalsefalseSharesxbrli:sharesItemTypesharesNumber of shares issued during the period related to Restricted Stock Awards, net of any shares forfeited.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 10 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 4, 5 falsefalseIssuance and forfeitures of restricted stock awards, net (in shares)37false0jns_AdjustmentsToRetainedEarningsCapitalTaxEffectFromShareBasedCompensationjnsfalsecreditdurationThis element represents the tax benefit associated with any share-based compensation plan other than an employee stock...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2truefalsefalse-6100000-6.1falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse-6100000-6.1falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis element represents the tax benefit associated with any share-based compensation plan other than an employee stock ownership plan (ESOP).No authoritative reference available.falsefalseTax impact of stock-based compensation38false0us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlanus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2truefalsefalse12000001.2falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse12000001.2falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryAggregate change in value for stock issued during the period as a result of employee stock purchase plan.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 10 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30, 31 -Article 5 falsefalseEmployee stock purchases39false0jns_MinorityInterestInConsolidatedInvestmentProductsjnsfalsecreditdurationNoncontrolling interests that are not subject to put rights consist of third party investors in consolidated investment...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4truefalsefalse-900000-0.9falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse-900000-0.9falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryNoncontrolling interests that are not subject to put rights consist of third party investors in consolidated investment products, certain third party interests granted to employees, and undistributed earnings attributable to such interests. Certain of the third party interests granted to employees will become subject to put rights upon vesting.No authoritative reference available.falsefalseNoncontrolling interests in consolidated investment products40false0us-gaap_MinorityInterestDecreaseFromRedemptionsus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4truefalsefalse-2300000-2.3falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse-2300000-2.3falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryDecrease in noncontrolling interest as a result of redeeming or purchasing the interests of noncontrolling shareholders.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(2) falsefalsePurchase of noncontrolling interests41false0us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHoldersus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4truefalsefalse-3200000-3.2falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse-3200000-3.2falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryDecrease in noncontrolling interest balance from payment of dividends or other distributions to noncontrolling interest holders.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(2) falsefalseDistributions to noncontrolling interests42false0us-gaap_MinorityInterestChangeInRedemptionValueus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2truefalsefalse-22800000-22.8falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse-22800000-22.8falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryChange in noncontrolling interest during the period as a result of a change in the redemption value of redeemable noncontrolling interest.No authoritative reference available.falsefalseChange in value of redeemable noncontrolling interests43false0us-gaap_DividendsCommonStockCashus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1falsefalsefalse00falsefalsefalsetruefalse2truefalsefalse-6500000-6.5falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse-6500000-6.5falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryCommon stock cash dividend declared by an entity during the period. This element includes paid and unpaid dividends declared during the period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 falsefalseCommon stock dividends ($0.04 per share)44false0us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestus-gaaptruecreditinstantNo definition available.falsefalsefalsetruefalsefalsefalsefalsetruefalseperiodendlabelinstant2009-12-31T00:00:000001-01-01T00:00:001truefalsefalse18000001.8falsefalsefalsetruefalse2truefalsefalse998300000998.3falsefalsefalsetruefalse3truefalsefalse10000001.0falsefalsefalsetruefalse4truefalsefalse1050000010.5falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse10116000001011.6falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryTotal of Stockholders' Equity (deficit) items, net of receivables from officers, directors owners, and affiliates of the entity including portions attributable to both the parent and noncontrolling interests (previously referred to as minority interest), if any. The entity including portions attributable to the parent and noncontrolling interests is sometimes referred to as the economic entity. This excludes temporary equity and is sometimes called permanent equity.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 25 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 26 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A3 -Appendix A falsefalseBalance at Dec. 31, 200945false0us-gaap_SharesIssuedus-gaaptruenainstantNo definition available.falsefalsefalsetruefalsefalsefalsefalsetruefalseperiodendlabelinstant2009-12-31T00:00:000001-01-01T00:00:001truefalsefalse182000000182.0falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsefalsefalseSharesxbrli:sharesItemTypesharesNumber of shares of stock issued as of the balance sheet date, including shares that had been issued and were previously outstanding but which are now held in the treasury.No authoritative reference available.falsefalseBalance (in shares) at Dec. 31, 200946true0us-gaap_IncreaseDecreaseInStockholdersEquityRollForwardus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringA roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.falsefalseIncrease (Decrease) in Stockholders' Equity47false0jns_NetIncomeLossExcludingRedeemableNoncontrollingInterestsjnsfalsecreditdurationThe portion of consolidated profit or loss for the period, net of income taxes, which is attributable to the parent,...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2truefalsefalse159900000159.9falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4truefalsefalse25000002.5falsefalsefalsetruefalse5truefalsefalse162400000162.4falsefalsefalsetruefalse6truefalsefalse162400000162.4falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe portion of consolidated profit or loss for the period, net of income taxes, which is attributable to the parent, excluding the effect of redeemable noncontrolling interests.No authoritative reference available.falsefalseNet income (loss) attributable to JCG48false0us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTaxus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3truefalsefalse7000000.7falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5truefalsefalse7000000.7falsefalsefalsetruefalse6truefalsefalse7000000.7falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryAppreciation or loss in value (before reclassification adjustment) of the total of unsold securities during the period being reported on, net of tax. Reclassification adjustments include: (1) the unrealized holding gain or loss, net of tax, at the date of the transfer for a debt security from the held-to-maturity category transferred into the available-for-sale category. Also includes the unrealized gain or loss at the date of transfer for a debt security from the available-for-sale category transferred into the held-to-maturity category; (2) the unrealized gains or losses realized upon the sale of securities, after tax; and (3) the unrealized gains or losses realized upon the write-down of securities, after tax.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 17, 22 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 13 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(3) Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 24 -Subparagraph b falsefalseNet unrealized gain (loss) on available-for-sale securities49false0us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecreaseus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3truefalsefalse2000000.2falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5truefalsefalse2000000.2falsefalsefalsetruefalse6truefalsefalse2000000.2falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryNet of tax effect change in accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges after taxes. A cash flow hedge is a hedge of the exposure to variability in the cash flows of a recognized asset or liability or a forecasted transaction that is attributable to a particular risk. The change includes an entity's share of an equity investee's increase (decrease) in deferred hedging gains or losses.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 14, 17, 20, 26 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 31, 46 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(3) Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 46 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 24 -Subparagraph b Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 14, 17, 20, 24, 26 falsefalseAmortization of net loss on cash flow hedge50false0us-gaap_OtherComprehensiveIncomeReclassificationAdjustmentForSaleOfSecuritiesIncludedInNetIncomeNetOfTaxus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3truefalsefalse-1400000-1.4falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5truefalsefalse-1400000-1.4falsefalsefalsetruefalse6truefalsefalse-1400000-1.4falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryReclassification adjustment for unrealized gains or losses realized upon the sale of securities, after tax.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(3) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 24 -Subparagraph b Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 18, 19 falsefalseReclassification for net gains included in net income51false0us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPeriodIncreaseDecreaseus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3truefalsefalse11000001.1falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5truefalsefalse11000001.1falsefalsefalsetruefalse6truefalsefalse11000001.1falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryAdjustment that results from the process of translating subsidiary financial statements and foreign equity investments into functional currency of the reporting entity, net of tax.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 52 -Paragraph 13, 20, 31 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(3) Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 24 -Subparagraph b Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 14, 17, 19, 26 falsefalseForeign currency translation adjustment52false0us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterestus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5truefalsefalse163000000163.0falsefalsefalsetruefalse6truefalsefalse163000000163.0falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the economic entity, including both controlling (parent) and noncontrolling interests. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, including any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A5 -Appendix A Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 29 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph a truefalseComprehensive income53false0jns_AdjustmentsToRetainedEarningsCapitalAmortizationOfShareBasedCompensationjnsfalsecreditdurationThis element represents the stock-based compensation cost which is based on the grant date fair value of awards expected to...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2truefalsefalse3340000033.4falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4truefalsefalse48000004.8falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse3820000038.2falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis element represents the stock-based compensation cost which is based on the grant date fair value of awards expected to vest at the end of the stated service period, comprised of the total value of the awards less an estimate for forfeitures. The grant date fair value of stock options is determined using the Black-Scholes option pricing model and the grant date fair value of restricted stock is determined from a quoted market price. The Black-Scholes model requires significant management estimates including volatility and expected life.No authoritative reference available.falsefalseAmortization of stock-based compensation54false0us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeituresus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse14000001.4falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsefalsefalseSharesxbrli:sharesItemTypesharesNumber of shares issued during the period related to Restricted Stock Awards, net of any shares forfeited.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 10 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 4, 5 falsefalseIssuance and forfeitures of restricted stock awards, net (in shares)55false0jns_AdjustmentsToRetainedEarningsCapitalTaxEffectFromShareBasedCompensationjnsfalsecreditdurationThis element represents the tax benefit associated with any share-based compensation plan other than an employee stock...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2truefalsefalse-5100000-5.1falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse-5100000-5.1falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis element represents the tax benefit associated with any share-based compensation plan other than an employee stock ownership plan (ESOP).No authoritative reference available.falsefalseTax impact of stock-based compensation56false0jns_StockOptionExercisesAndEmployeeStockPurchasesjnsfalsecreditdurationValue stock issued during the period as a result of the exercise of stock options and as a result of stock issued during the...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2truefalsefalse44000004.4falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse44000004.4falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryValue stock issued during the period as a result of the exercise of stock options and as a result of stock issued during the period for an employee stock purchase plan.No authoritative reference available.falsefalseStock option exercises and employee stock purchases57false0jns_StockOptionExercisesAndEmployeeStockPurchasesSharesjnsfalsenadurationNumber of shares issued during the period as a result of the exercise of stock options and purchases through an employee...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse7000000.7falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsefalsefalseSharesxbrli:sharesItemTypesharesNumber of shares issued during the period as a result of the exercise of stock options and purchases through an employee stock purchase plan.No authoritative reference available.falsefalseStock option exercises and employee stock purchases (in shares)58false0jns_MinorityInterestInConsolidatedInvestmentProductsjnsfalsecreditdurationNoncontrolling interests that are not subject to put rights consist of third party investors in consolidated investment...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4truefalsefalse33000003.3falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse33000003.3falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryNoncontrolling interests that are not subject to put rights consist of third party investors in consolidated investment products, certain third party interests granted to employees, and undistributed earnings attributable to such interests. Certain of the third party interests granted to employees will become subject to put rights upon vesting.No authoritative reference available.falsefalseNoncontrolling interests in consolidated investment products59false0us-gaap_MinorityInterestDecreaseFromRedemptionsus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4truefalsefalse-5000000-5.0falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse-5000000-5.0falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryDecrease in noncontrolling interest as a result of redeeming or purchasing the interests of noncontrolling shareholders.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(2) falsefalsePurchase of noncontrolling interests60false0us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHoldersus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1falsefalsefalse00falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4truefalsefalse-3200000-3.2falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse-3200000-3.2falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryDecrease in noncontrolling interest balance from payment of dividends or other distributions to noncontrolling interest holders.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(2) falsefalseDistributions to noncontrolling interests61false0us-gaap_MinorityInterestChangeInRedemptionValueus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2truefalsefalse-16600000-16.6falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse-16600000-16.6falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryChange in noncontrolling interest during the period as a result of a change in the redemption value of redeemable noncontrolling interest.No authoritative reference available.falsefalseChange in value of redeemable noncontrolling interests62false0jns_MinorityInterestDecreaseFromVestingOfNoncontrollingInterestjnsfalsecreditdurationDecrease in noncontrolling interest as a result of the vesting interest of a majority owned subsidiary.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsetruefalse2truefalsefalse12000001.2falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4truefalsefalse-1200000-1.2falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryDecrease in noncontrolling interest as a result of the vesting interest of a majority owned subsidiary.No authoritative reference available.falsefalseVesting of Perkins LLC interests63false0us-gaap_DividendsCommonStockCashus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1falsefalsefalse00falsefalsefalsetruefalse2truefalsefalse-7400000-7.4falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse-7400000-7.4falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryCommon stock cash dividend declared by an entity during the period. This element includes paid and unpaid dividends declared during the period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 falsefalseCommon stock dividends ($0.04 per share)64false0us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestus-gaaptruecreditinstantNo definition available.falsefalsefalsetruefalsefalsefalsefalsetruefalseperiodendlabelinstant2010-12-31T00:00:000001-01-01T00:00:001truefalsefalse18000001.8falsetruefalsetruefalse2truefalsefalse11681000001168.1falsetruefalsetruefalse3truefalsefalse16000001.6falsetruefalsetruefalse4truefalsefalse1170000011.7falsetruefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6truefalsefalse11832000001183.2falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryTotal of Stockholders' Equity (deficit) items, net of receivables from officers, directors owners, and affiliates of the entity including portions attributable to both the parent and noncontrolling interests (previously referred to as minority interest), if any. The entity including portions attributable to the parent and noncontrolling interests is sometimes referred to as the economic entity. This excludes temporary equity and is sometimes called permanent equity.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 25 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 26 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A3 -Appendix A falsefalseBalance at Dec. 31, 201065false0us-gaap_SharesIssuedus-gaaptruenainstantNo definition available.falsefalsefalsetruefalsefalsefalsefalsetruefalseperiodendlabelinstant2010-12-31T00:00:000001-01-01T00:00:001truefalsefalse184100000184.1falsefalsefalsetruefalse2falsefalsefalse00falsefalsefalsetruefalse3falsefalsefalse00falsefalsefalsetruefalse4falsefalsefalse00falsefalsefalsetruefalse5falsefalsefalse00falsefalsefalsetruefalse6falsefalsefalse00falsefalsefalsefalsefalseSharesxbrli:sharesItemTypesharesNumber of shares of stock issued as of the balance sheet date, including shares that had been issued and were previously outstanding but which are now held in the treasury.No authoritative reference available.falsefalseBalance (in shares) at Dec. 31, 2010665CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (USD $)HundredThousandsHundredThousandsUnKnownUnKnownfalsetrue