Fair value of financial instruments - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2026	Jul. 26, 2023
G4S
Derivative [Line Items]
Contingent consideration	$ 24
Foreign Exchange Contract \| Not Designated as Hedging Instrument
Derivative [Line Items]
Notional value of nonderivative instruments	$ 653
Weighted average maturity	1 month
$215 million cross currency swap II \| Designated as Hedging Instrument
Derivative [Line Items]
Weighted average maturity	1 month 6 days
Notional value of derivative instrument	$ 215	$ 215
$215 million cross currency swap \| Designated as Hedging Instrument
Derivative [Line Items]
Notional value of derivative instrument		$ 215
$150 million interest rate swap \| Designated as Hedging Instrument
Derivative [Line Items]
Weighted average maturity	8 months 12 days
Notional value of derivative instrument	$ 150

Amount of liability recognized arising from contingent consideration in a business combination.

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