No definition available.

Name:	alsn_GainLossOnForeignExchange
Namespace Prefix:	alsn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Gain losses on assets held under trust for a nonqualified deferred compensation plans.

No definition available.

Name:	alsn_GainLossesOnAssetsHeldUnderTrustForANonqualifiedDeferredCompensationPlans
Namespace Prefix:	alsn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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Other Income (Expense), Post-Retirement Benefit Plan Amendment Credits

No definition available.

Name:	alsn_OtherIncomeExpensePostRetirementBenefitPlanAmendmentCredits
Namespace Prefix:	alsn_
Data Type:	xbrli:monetaryItemType
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Technology related investments loss (gain).

No definition available.

Name:	alsn_TechnologyRelatedInvestmentsLossGain
Namespace Prefix:	alsn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of unrealized gain (loss) on investment in marketable security.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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- References

No definition available.

Name:	us-gaap_OtherIncomeAndExpensesAbstract
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Data Type:	xbrli:stringItemType
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Amount of gain (loss) related to nonoperating activities, classified as other.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(7))
-Publisher FASB
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
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-Publisher FASB
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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Amount of income (expense) related to nonoperating activities, classified as other.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4A
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(9))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2

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