Segment information - Narrative (Details)	6 Months Ended	12 Months Ended
Dec. 31, 2022 business_group	Dec. 31, 2021 division	Dec. 31, 2021 divisions
Disclosure of operating segments [abstract]
Number of business groups	5
Number of divisions included in cash generating units		3	3

Number of divisions included in cash generating units.

No definition available.

Name:	ul_NumberOfDivisionsIncludedInCashGeneratingUnits
Namespace Prefix:	ul_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration