Restructuring - Narrative (Details) $ in Millions	6 Months Ended
Restructuring - Narrative (Details) $ in Millions	Jun. 30, 2026 USD ($)
Phase I of the Indivior Action Agenda
Restructuring Cost and Reserve [Line Items]
Cumulative restructuring charges incurred since inception	$ 140
Restructuring charges	13
Additional costs expected	0
Phase I of the Indivior Action Agenda \| Location, Statement of Income, Balance [Axis]: us-gaap:ResearchAndDevelopmentExpenseExcludingAcquiredInProcessCost
Restructuring Cost and Reserve [Line Items]
Restructuring charges	9
Phase I of the Indivior Action Agenda \| Location, Statement of Income, Balance [Axis]: us-gaap:SellingGeneralAndAdministrativeExpense
Restructuring Cost and Reserve [Line Items]
Restructuring charges	4
Cease Phase 3 Development of INDV-6001 and Not Advance INDV-2000 Internally
Restructuring Cost and Reserve [Line Items]
Cumulative restructuring charges incurred since inception	6
Additional costs expected	0
Cease Phase 3 Development of INDV-6001 and Not Advance INDV-2000 Internally \| Location, Statement of Income, Balance [Axis]: us-gaap:ResearchAndDevelopmentExpenseExcludingAcquiredInProcessCost
Restructuring Cost and Reserve [Line Items]
Restructuring charges	5
Cease Phase 3 Development of INDV-6001 and Not Advance INDV-2000 Internally \| Location, Statement of Income, Balance [Axis]: us-gaap:SellingGeneralAndAdministrativeExpense
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 1

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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