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Income Taxes - Reconciled Tax at Statutory Rates (Detail) (USD $)
In Millions, unless otherwise specified |
12 Months Ended | ||
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Mar. 31, 2015
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Mar. 31, 2014
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Mar. 31, 2013
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| Income Tax Disclosure [Abstract] | |||
| Income tax (expense) benefit at statutory tax rates | $ (75.0)us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate | $ 6.2us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate | $ 8.8us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate |
| US state income taxes, net of the federal benefit | (2.4)us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes | (1.8)us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes | (0.1)us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes |
| Asbestos adjustments | 48.3jhx_IncomeTaxReconciliationAsbestosAdjustments | 30.2jhx_IncomeTaxReconciliationAsbestosAdjustments | (0.3)jhx_IncomeTaxReconciliationAsbestosAdjustments |
| Expenses not deductible | (3.4)us-gaap_IncomeTaxReconciliationNondeductibleExpense | (2.1)us-gaap_IncomeTaxReconciliationNondeductibleExpense | (2.0)us-gaap_IncomeTaxReconciliationNondeductibleExpense |
| Non-assessable items | 0.5jhx_IncomeTaxReconciliationNonAssessableItems | 0.6jhx_IncomeTaxReconciliationNonAssessableItems | 1.8jhx_IncomeTaxReconciliationNonAssessableItems |
| Foreign taxes on domestic income | (0.7)jhx_IncomeTaxReconciliationForeignTaxesOnDomesticIncome | ||
| Amortization of intangibles | 2.8jhx_IncomeTaxReconciliationAmortizationOfIntangibles | 1.7jhx_IncomeTaxReconciliationAmortizationOfIntangibles | 2.0jhx_IncomeTaxReconciliationAmortizationOfIntangibles |
| Taxes on foreign income | (4.5)jhx_IncomeTaxReconciliationTaxesOnForeignIncome | (2.9)jhx_IncomeTaxReconciliationTaxesOnForeignIncome | 1.1jhx_IncomeTaxReconciliationTaxesOnForeignIncome |
| Tax assessment in dispute | 10.7jhx_IncomeTaxReconciliationTaxAssessmentsInDispute | ||
| Other items | 3.1us-gaap_IncomeTaxReconciliationOtherAdjustments | 2.3us-gaap_IncomeTaxReconciliationOtherAdjustments | 0.5us-gaap_IncomeTaxReconciliationOtherAdjustments |
| Total income tax (expense) benefit | $ (31.3)us-gaap_IncomeTaxExpenseBenefit | $ 44.9us-gaap_IncomeTaxExpenseBenefit | $ 11.8us-gaap_IncomeTaxExpenseBenefit |
| Effective tax rate | 9.70%us-gaap_EffectiveIncomeTaxRateContinuingOperations | (82.20%)us-gaap_EffectiveIncomeTaxRateContinuingOperations | (35.00%)us-gaap_EffectiveIncomeTaxRateContinuingOperations |
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- Definition
Income tax reconciliation amortization of intangibles. No definition available.
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- Definition
Income tax reconciliation asbestos adjustments. No definition available.
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- Definition
Income tax reconciliation foreign taxes on domestic income No definition available.
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- Definition
Income tax reconciliation non assessable items. No definition available.
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- Definition
Tax assessment in dispute related to Australian Taxation Office - Amended Assessment. No definition available.
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- Definition
Taxes on subsidiary foreign income and withholding taxes paid or accrued on foreign interest, royalties and dividends. No definition available.
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- Definition
Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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- Definition
Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to nondeductible expenses. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to other adjustments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to state and local income tax expense (benefit). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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