Leases - Components of lease expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Components of lease expense
Operating lease expense	$ (98)	$ (100)
Finance lease expense	(4)	(2)
Variable lease expense	(11)	(10)
Sublease income	2	3
Net lease expense	$ (111)	$ (109)