Income taxes - Valuation Allowance Activity (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 29, 2024	Dec. 31, 2023
Valuation Allowance [Roll Forward]
Beginning of year	$ 1,149	$ 775
Provision	451	355
Utilization	0	(116)
Foreign currency translation	(46)	25
Net acquisitions / (dispositions/liquidations)	84	110
End of year	$ 1,638	$ 1,149

Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-2

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant