Share-based compensation - Share-based Compensation Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation	$ 143	$ 125	$ 123
2025 Equity Incentive Plan (EIP)
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation	38	0	0
Performance Share Plan expense | 2014 Performance Share Plan (PSP)
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation	104	123	120
Share Option expense
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation	$ 1	$ 2	$ 3