Fair value of assets held by international pension plans (Details) - Foreign Plan - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 583	$ 594
Level 1
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	5	1
Level 2
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	17	20
Level 3
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	561	565
Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	8
Cash and equivalents
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	8	0
Cash and equivalents | Level 1
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	4	0
Cash and equivalents | Level 2
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	4	0
Cash and equivalents | Level 3
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Cash and equivalents | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Bond funds
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	4	11
Bond funds | Level 1
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Bond funds | Level 2
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	4	11
Bond funds | Level 3
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Bond funds | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Real estate funds
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	8
Real estate funds | Level 1
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Real estate funds | Level 2
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Real estate funds | Level 3
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Real estate funds | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	8
Other Investments
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	571	575
Other Investments | Level 1
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	1	1
Other Investments | Level 2
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	9	9
Other Investments | Level 3
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	561	565
Other Investments | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 0	$ 0