Employees - Summary of Staff Cost and Average Number of Employees (Details) Employees in Thousands, € in Millions	12 Months Ended
Dec. 31, 2024 EUR (€) Employees	Dec. 31, 2023 EUR (€) Employees	Dec. 31, 2022 EUR (€) Employees
Disclosure Of Staff And Management Costs [Line Items]
Wages and salaries	€ (5,852)	€ (5,722)	€ (5,857)
Social security costs	(640)	(591)	(587)
Other pension costs	(339)	(348)	(396)
Share-based compensation costs	(324)	(212)	(177)
Gross staff costs	€ (7,155)	€ (6,873)	€ (7,017)
Average number of employees during the year \| Employees	125	128	138
Asia Pacific Africa
Disclosure Of Staff And Management Costs [Line Items]
Average number of employees during the year \| Employees	61	64	73
The Americas
Disclosure Of Staff And Management Costs [Line Items]
Average number of employees during the year \| Employees	38	38	38
Europe
Disclosure Of Staff And Management Costs [Line Items]
Average number of employees during the year \| Employees	26	26	27

The average number of personnel employed by the entity during a period.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 112
-Subparagraph c
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_112_c&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_AverageNumberOfEmployees
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

The expense of all forms of consideration given by an entity in exchange for a service rendered by employees or for the termination of employment.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 102
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_102&doctype=Standard
-URIDate 2024-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 99
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_99&doctype=Standard
-URIDate 2024-03-27

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 104
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_104&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_EmployeeBenefitsExpense
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of expense from share-based payment transactions with employees. [Refer: Expense from share-based payment transactions]

+ References

+ Details

Name:	ifrs-full_ExpenseFromSharebasedPaymentTransactionsWithEmployees
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

A class of employee benefits expense that represents social security contributions. [Refer: Employee benefits expense]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2024-01-01
-Paragraph 9
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2024-en-r&anchor=para_9&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_SocialSecurityContributions
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

A class of employee benefits expense that represents wages and salaries. [Refer: Employee benefits expense]

+ References

+ Details

Name:	ifrs-full_WagesAndSalaries
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Disclosure Of Staff And Management Costs [Line Items]

+ References

No definition available.

+ Details

Name:	ul_DisclosureOfStaffAndManagementCostsLineItems
Namespace Prefix:	ul_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Post employment benefit costs.

+ References

No definition available.

+ Details

Name:	ul_PostEmploymentBenefitCosts
Namespace Prefix:	ul_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	ifrs-full_GeographicalAreasAxis=ul_AsiaPacificAndAfricaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_GeographicalAreasAxis=srt_AmericasMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_GeographicalAreasAxis=srt_EuropeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: