Pension and postretirement benefits - Components of Plan Benefit Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 28, 2024	Sep. 30, 2023	Sep. 28, 2024	Sep. 30, 2023
Pension
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, net periodic benefit cost (credit)	$ 7	$ 1	$ 9	$ 1
Multiemployer plan, employer contribution, cost (credit)		12		16
Nonpension postretirement
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, net periodic benefit cost (credit)	$ (10)	(6)	$ (30)	(6)
Multiemployer plan, employer contribution, cost (credit)		(37)		(52)
Gain (loss) recognized in cost of goods sold | Pension
Defined Benefit Plan Disclosure [Line Items]
Multiemployer plan, employer contribution, cost (credit)		1		5
Gain (loss) recognized in cost of goods sold | Nonpension postretirement
Defined Benefit Plan Disclosure [Line Items]
Multiemployer plan, employer contribution, cost (credit)		1		3
Gain (loss) recognized in other income (expense), net | Pension
Defined Benefit Plan Disclosure [Line Items]
Multiemployer plan, employer contribution, cost (credit)		10		10
Gain (loss) recognized in other income (expense), net | Nonpension postretirement
Defined Benefit Plan Disclosure [Line Items]
Multiemployer plan, employer contribution, cost (credit)		$ (44)		$ (65)