Pension and other postretirement benefits - Impact on Consolidated Statements of Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Total defined contribution expense	$ 345	$ 320	$ 307
Total defined benefit expense	34	31	30
Continuing Operations [Member]
Defined Benefit Plan Disclosure [Line Items]
Total expense within the Consolidated Statements of Income	$ 379	$ 351	$ 337