Summary of significant accounting policies - Narrative (Details) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2024 USD ($) segment	Dec. 31, 2024 USD ($) segment	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Variable Interest Entity [Line Items]
Number of reportable segments | segment	3	3
China investment
Variable Interest Entity [Line Items]
Difference between carrying amount and underlying equity	$ 190	$ 190
Other-than-temporary impairment		190	$ 0	$ 0
Designated as hedging instrument | Fair value hedging
Variable Interest Entity [Line Items]
Derivative, notional amount	1,375	1,375	1,375
Designated as hedging instrument | Cash flow hedging
Variable Interest Entity [Line Items]
Derivative, notional amount	342	342	550
Designated as hedging instrument | Net investment hedging
Variable Interest Entity [Line Items]
Derivative, notional amount	1,371	1,371	1,187
Not designated as hedging instrument
Variable Interest Entity [Line Items]
Derivative, notional amount	$ 3,323	$ 3,323	$ 338
Minimum | Customer-related
Variable Interest Entity [Line Items]
Finite-lived intangible asset, useful life	5 years	5 years
Minimum | Marketing-related
Variable Interest Entity [Line Items]
Finite-lived intangible asset, useful life	10 years	10 years
Maximum | Customer-related
Variable Interest Entity [Line Items]
Finite-lived intangible asset, useful life	20 years	20 years
Maximum | Marketing-related
Variable Interest Entity [Line Items]
Finite-lived intangible asset, useful life	30 years	30 years
Building
Variable Interest Entity [Line Items]
Property, plant and equipment, useful life	40 years	40 years
Plant and machinery | Minimum
Variable Interest Entity [Line Items]
Property, plant and equipment, useful life	5 years	5 years
Plant and machinery | Maximum
Variable Interest Entity [Line Items]
Property, plant and equipment, useful life	30 years	30 years