Segments and Disaggregation of Revenue - Schedule of Reconciliation of Reportable Segment Adjusted EBITDA to Loss Before Taxes (Detail) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Reportable segment adjusted EBITDA	$ 550	$ 387
Unallocated corporate overhead	(36)	(35)
Depreciation and amortization	(297)	(297)
Share-based compensation expense	(41)	(46)
Transaction fees and associated costs	(29)	(3)
Restructuring and integration costs	(23)	(21)
Other expense, net	(174)	(45)
Interest expense, net	(112)	(92)
Loss before income taxes	(162)	(152)
US [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Reportable segment adjusted EBITDA	26	(53)
UK [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Reportable segment adjusted EBITDA	268	206
Australia [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Reportable segment adjusted EBITDA	83	85
International Segement [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Reportable segment adjusted EBITDA	173	149
Segment Reconciling Items [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest expense, net	$ (112)	$ (92)

Earnings before interest tax depreciation and amortization.

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Unallocated corporate overhead.

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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The net amount of nonoperating interest income (expense).

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A fee charged for services from professionals such as doctors, lawyers and accountants. The term is often expanded to include other professions, for example, pharmacists charging to maintain a medicinal profile of a client or customer.

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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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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