Intangible assets - Key assumptions used by individual CGUs for value-in-use calculations (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
North America
Intangible assets
Long-term growth rate	2.00%
North America \| US Pest Control
Intangible assets
Long-term growth rate	2.00%	2.20%
Pre-tax discount rate	10.30%	7.70%
Headroom amount	£ 1,692	£ 2,121
North America \| Minimum
Intangible assets
Long-term growth rate		2.00%
Pre-tax discount rate	8.40%	6.60%
North America \| Maximum
Intangible assets
Long-term growth rate		2.20%
Pre-tax discount rate	10.30%	8.70%
Europe \| Minimum
Intangible assets
Long-term growth rate	1.30%	1.30%
Pre-tax discount rate	6.70%	7.10%
Europe \| Maximum
Intangible assets
Long-term growth rate	3.00%	3.30%
Pre-tax discount rate	15.40%	15.40%
UK & Sub Saharan Africa \| Minimum
Intangible assets
Long-term growth rate	2.00%	2.00%
Pre-tax discount rate	8.00%	6.50%
UK & Sub Saharan Africa \| Maximum
Intangible assets
Long-term growth rate	4.50%	4.50%
Pre-tax discount rate	12.30%	11.60%
Asia & MENAT \| Minimum
Intangible assets
Long-term growth rate	1.50%	1.50%
Pre-tax discount rate	9.70%	8.20%
Asia & MENAT \| Maximum
Intangible assets
Long-term growth rate	4.00%	4.00%
Pre-tax discount rate	13.90%	12.60%
Pacific \| Minimum
Intangible assets
Long-term growth rate	2.00%	2.20%
Pre-tax discount rate	10.20%	9.30%
Pacific \| Maximum
Intangible assets
Long-term growth rate	2.50%	2.40%
Pre-tax discount rate	11.00%	10.70%

The amount by which a cash-generating unit's (group of units') recoverable amount exceeds its carrying amount. [Refer: Carrying amount [member]; Cash-generating units [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 36
-IssueDate 2023-01-01
-Paragraph 134
-Subparagraph f
-Clause i
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2023-en-r&anchor=para_134_f_i&doctype=Standard
-URIDate 2023-03-23

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 36
-IssueDate 2023-01-01
-Paragraph 135
-Subparagraph e
-Clause i
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2023-en-r&anchor=para_135_e_i&doctype=Standard
-URIDate 2023-03-23

+ Details

Name:	ifrs-full_AmountByWhichUnitsRecoverableAmountExceedsItsCarryingAmount
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The discount rate applied to cash flow projections for a cash-generating unit (group of units). [Refer: Cash-generating units [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 36
-IssueDate 2023-01-01
-Paragraph 134
-Subparagraph d
-Clause v
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2023-en-r&anchor=para_134_d_v&doctype=Standard
-URIDate 2023-03-23

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 36
-IssueDate 2023-01-01
-Paragraph 134
-Subparagraph e
-Clause v
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2023-en-r&anchor=para_134_e_v&doctype=Standard
-URIDate 2023-03-23

+ Details

Name:	ifrs-full_DescriptionOfDiscountRatesAppliedToCashFlowProjections
Namespace Prefix:	ifrs-full_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The growth rate used to extrapolate cash flow projections beyond the period covered by the most recent budgets/forecasts for a cash-generating unit (group of units). [Refer: Cash-generating units [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 36
-IssueDate 2023-01-01
-Paragraph 134
-Subparagraph d
-Clause iv
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2023-en-r&anchor=para_134_d_iv&doctype=Standard
-URIDate 2023-03-23

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 36
-IssueDate 2023-01-01
-Paragraph 134
-Subparagraph e
-Clause iv
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2023-en-r&anchor=para_134_e_iv&doctype=Standard
-URIDate 2023-03-23

+ Details

Name:	ifrs-full_DescriptionOfGrowthRateUsedToExtrapolateCashFlowProjections
Namespace Prefix:	ifrs-full_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table.

+ References

No definition available.

+ Details

Name:	ifrs-full_DisclosureOfInformationForEachMaterialImpairmentLossRecognisedOrReversedForIndividualAssetOrCashgeneratingUnitLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Details

Name:	ifrs-full_IndividualAssetsOrCashgeneratingUnitsWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesAxis=rto_UsPestControlMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_RangeAxis=ifrs-full_BottomOfRangeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_RangeAxis=ifrs-full_TopOfRangeMember
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:

- Details

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

- Details

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

- Details

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