Intangible assets (Tables)

12 Months Ended

Dec. 31, 2025

Disclosure of detailed information about intangible assets [abstract]

Schedule of components and movements during the period in intangible assets

Cost:

		Balance at January 1, 2025				Additions				Effect of movements in exchange rates				Balance at December 31, 2025
		US $ in millions
Software (mostly development costs)			289.5				19.6				(0.1	)			309.0
Other intangible assets			3.4												3.4
Total			292.9				19.6				(0.1	)			312.4

Amortization and impairment charges:

		Balance at January 1, 2025				Amortization				Effect of movements in exchange rates				Balance at December 31, 2025
		US $ in millions
Software (mostly development costs)			179.9				19.7								199.6
Other intangible assets			3.2				0.2								3.4
Total			183.1				19.9								203.0

Net carrying amounts:

		Balance at January 1, 2025												Balance at December 31, 2025
		US $ in millions												US $ in millions

Software (mostly development costs)			109.6												109.4
Other intangible assets			0.2
Total			109.8												109.4

Cost:

		Balance at January 1, 2024				Additions				Disposals				Effect of movements in exchange rates				Balance at December 31, 2024


		US $ in millions
Software (mostly development costs)			268.4				21.2								(0.1	)			289.5
Other intangible assets			4.5								(1.1	)							3.4
Total			272.9				21.2				(1.1	)			(0.1	)			292.9

Amortization and impairment charges:

		Balance at January 1, 2024				Amortization				Disposals				Effect of movements in exchange rates				Balance at December 31, 2024
		US $ in millions
Software (mostly development costs)			166.7				13.4								(0.2	)			179.9
Other intangible assets			4.2				0.1				(1.1	)							3.2
Total			170.9				13.5				(1.1	)			(0.2	)			183.1

Net carrying amounts:

		Balance at January 1, 2024																Balance at December 31, 2024
		US $ in millions																US $ in millions

Software (mostly development costs)			101.7																109.6
Other intangible assets			0.3																0.2
Total			102.0																109.8