Derivative instruments and hedge accounting - Schedule of derivative instruments in statement of financial position (Details) - USD ($) $ in Millions	Sep. 30, 2026	Dec. 31, 2025
Derivatives, Fair Value [Line Items]
Notional amount	$ 3,940.8	$ 2,776.5
Derivative assets	39.9	3.8
Derivative liabilities	49.0	7.9
Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherAssetsCurrent
Derivatives, Fair Value [Line Items]
Derivative assets	0.0	3.7
Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherAssetsNoncurrent
Derivatives, Fair Value [Line Items]
Derivative assets	39.9	0.1
Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent
Derivatives, Fair Value [Line Items]
Derivative liabilities	(31.8)	(0.3)
Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent
Derivatives, Fair Value [Line Items]
Derivative liabilities	(17.2)	(7.6)
Interest rate swaps
Derivatives, Fair Value [Line Items]
Notional amount	1,819.3	1,849.8
Derivative assets	39.9	0.1
Derivative liabilities	0.0	7.3
Interest rate swaps \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherAssetsCurrent
Derivatives, Fair Value [Line Items]
Derivative assets	0.0	0.0
Interest rate swaps \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherAssetsNoncurrent
Derivatives, Fair Value [Line Items]
Derivative assets	39.9	0.1
Interest rate swaps \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent
Derivatives, Fair Value [Line Items]
Derivative liabilities	0.0	0.0
Interest rate swaps \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent
Derivatives, Fair Value [Line Items]
Derivative liabilities	0.0	(7.3)
Interest rate swaps (Euribor)
Derivatives, Fair Value [Line Items]
Notional amount	874.3	904.8
Interest rate swaps (Euribor) \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherAssetsCurrent
Derivatives, Fair Value [Line Items]
Derivative assets	0.0	0.0
Interest rate swaps (Euribor) \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherAssetsNoncurrent
Derivatives, Fair Value [Line Items]
Derivative assets	17.9	0.1
Interest rate swaps (Euribor) \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent
Derivatives, Fair Value [Line Items]
Derivative liabilities	0.0	0.0
Interest rate swaps (Euribor) \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent
Derivatives, Fair Value [Line Items]
Derivative liabilities	0.0	(2.5)
Interest rate swaps (SOFR)
Derivatives, Fair Value [Line Items]
Notional amount	945.0	945.0
Interest rate swaps (SOFR) \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherAssetsCurrent
Derivatives, Fair Value [Line Items]
Derivative assets	0.0	0.0
Interest rate swaps (SOFR) \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherAssetsNoncurrent
Derivatives, Fair Value [Line Items]
Derivative assets	22.0	0.0
Interest rate swaps (SOFR) \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent
Derivatives, Fair Value [Line Items]
Derivative liabilities	0.0	0.0
Interest rate swaps (SOFR) \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent
Derivatives, Fair Value [Line Items]
Derivative liabilities	0.0	(4.8)
Foreign currency hedges
Derivatives, Fair Value [Line Items]
Notional amount	2,121.5	926.7
Derivative assets	0.0	3.7
Derivative liabilities	49.0	0.6
Foreign currency hedges \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherAssetsCurrent
Derivatives, Fair Value [Line Items]
Derivative assets	0.0	3.7
Foreign currency hedges \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherAssetsNoncurrent
Derivatives, Fair Value [Line Items]
Derivative assets	0.0	0.0
Foreign currency hedges \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent
Derivatives, Fair Value [Line Items]
Derivative liabilities	(31.8)	(0.3)
Foreign currency hedges \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ (17.2)	$ (0.3)