Classification and measurement of financial instruments - Summary of Fair Value Measurement Hierarchy of Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Assets
Derivative financial instruments	$ 1	$ 8
Liabilities
Derivative financial instruments	(20)
Contingent purchase consideration	(91)	(109)
Deferred purchase consideration	(23)	(22)
Loans and other borrowings	(2,165)	(2,014)
Deferred purchase consideration [member]
Liabilities
Deferred purchase consideration	(23)	(22)
Money Market Fund [Member]
Assets
Financial assets	51	92
Quoted equity shares [member]
Assets
Equity securities	133	116
Financial assets at fair value through profit or loss, category [member]
Assets
Financial assets	55	100
Financial assets at fair value through profit or loss, category [member] \| Money Market Fund [Member]
Assets
Financial assets	3
Financial assets at fair value through profit or loss, category [member] \| Trade deposits and loans [member]
Assets
Financial assets	3
GBP400m 3.875% bonds 2022 [member]
Liabilities
Loans and other borrowings	(528)	(509)
GBP300m 3.75% bonds 2025 [member]
Liabilities
Loans and other borrowings	(399)	(385)
GBP350m 2.125% bonds 2026 [member]
Liabilities
Loans and other borrowings	(462)	(447)
EUR500m 2.125% bonds 2027 [member]
Liabilities
Loans and other borrowings	(564)	(569)
Fair value [member]
Liabilities
Derivative financial instruments	(20)
Contingent purchase consideration	(91)	(109)
Deferred purchase consideration	(24)	(22)
Fair value [member] \| Money Market Fund [Member]
Assets
Financial assets	51	92
Fair value [member] \| Trade deposits and loans [member]
Assets
Financial assets	3
Fair value [member] \| Derivative financial assets [member]
Assets
Derivative financial instruments	1	8
Fair value [member] \| Quoted equity shares [member]
Assets
Equity securities	133	116
Fair value [member] \| GBP400m 3.875% bonds 2022 [member]
Liabilities
Loans and other borrowings	(567)	(543)
Fair value [member] \| GBP300m 3.75% bonds 2025 [member]
Liabilities
Loans and other borrowings	(435)	(399)
Fair value [member] \| GBP350m 2.125% bonds 2026 [member]
Liabilities
Loans and other borrowings	(465)	(417)
Fair value [member] \| EUR500m 2.125% bonds 2027 [member]
Liabilities
Loans and other borrowings	(601)	(566)
Level 1 [member] \| Fair value [member]
Liabilities
Deferred purchase consideration	(24)	(22)
Level 1 [member] \| Fair value [member] \| Money Market Fund [Member]
Assets
Financial assets	51	92
Level 1 [member] \| Fair value [member] \| Quoted equity shares [member]
Assets
Equity securities	8	8
Level 1 [member] \| Fair value [member] \| GBP400m 3.875% bonds 2022 [member]
Liabilities
Loans and other borrowings	(567)	(543)
Level 1 [member] \| Fair value [member] \| GBP300m 3.75% bonds 2025 [member]
Liabilities
Loans and other borrowings	(435)	(399)
Level 1 [member] \| Fair value [member] \| GBP350m 2.125% bonds 2026 [member]
Liabilities
Loans and other borrowings	(465)	(417)
Level 1 [member] \| Fair value [member] \| EUR500m 2.125% bonds 2027 [member]
Liabilities
Loans and other borrowings	(601)	(566)
Level 2 [member] \| Fair value [member]
Liabilities
Derivative financial instruments	(20)
Level 2 [member] \| Fair value [member] \| Quoted equity shares [member]
Assets
Derivative financial instruments	1	8
Level 3 [member] \| Trade deposits and loans [member]
Assets
Financial assets	3
Level 3 [member] \| Fair value [member]
Liabilities
Contingent purchase consideration	(91)	(109)
Level 3 [member] \| Fair value [member] \| Quoted equity shares [member]
Assets
Equity securities	$ 125	$ 108

The amount of outstanding funds that the entity is obligated to repay.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 55
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_55&doctype=Standard
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_Borrowings
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

The amount of financial assets classified as derivative instruments. [Refer: Financial assets; Derivatives [member]]

+ References

+ Details

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

- Definition

The amount of financial liabilities classified as derivative instruments. [Refer: Financial assets; Derivatives [member]]

+ References

+ Details

Name:	ifrs-full_DerivativeFinancialLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

The amount of assets that are: (a) cash; (b) an equity instrument of another entity; (c) a contractual right: (i) to receive cash or another financial asset from another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially favourable to the entity; or (d) a contract that will, or may be, settled in the entity’s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to receive a variable number of the entity’s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity’s own equity instruments. For this purpose the entity’s own equity instruments do not include puttable financial instruments classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity’s own equity instruments. [Refer: Financial instruments, class [member]; Financial liabilities]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2019-01-01
-Paragraph 25
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2019-en-r&anchor=para_25&doctype=Standard
-URIDate 2019-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2019-01-01
-Paragraph 35H
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2019-en-r&anchor=para_35H&doctype=Standard
-URIDate 2019-03-27

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2019-01-01
-Paragraph 35I
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2019-en-r&anchor=para_35I&doctype=Standard
-URIDate 2019-03-27

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2019-01-01
-Paragraph 35M
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2019-en-r&anchor=para_35M&doctype=Standard
-URIDate 2019-03-27

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Name IFRS
-Number 7
-IssueDate 2019-01-01
-Paragraph 35N
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2019-en-r&anchor=para_35N&doctype=Standard
-URIDate 2019-03-27

+ Details

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

- Definition

The amount of payables for the purchase of non-current assets. [Refer: Non-current assets]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 78
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_78&doctype=Standard
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_PayablesForPurchaseOfNoncurrentAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Deferred purchase consideration.

+ References

No definition available.

+ Details

Name:	ihg_DeferredPurchaseConsideration
Namespace Prefix:	ihg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Equity securities at fair value.

+ References

No definition available.

+ Details

Name:	ihg_EquitySecuritiesAtFairValue
Namespace Prefix:	ihg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	ifrs-full_CategoriesOfFinancialLiabilitiesAxis=ihg_DeferredPurchaseConsiderationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfAssetsAxis=ihg_MoneyMarketFundMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_CategoriesOfFinancialAssetsAxis=ihg_QuotedEquitySharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_CategoriesOfFinancialAssetsAxis=ifrs-full_FinancialAssetsAtFairValueThroughProfitOrLossCategoryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfAssetsAxis=ihg_TradeDepositsAndLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_BorrowingsByNameAxis=ihg_FourHundredMillionPoundThreePointEightSevenFivePercentageBondsDueInTwoThousandTwentyTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_BorrowingsByNameAxis=ihg_ThreeHundredMillionPoundThreePointSevenFivePercentageBondsDueInTwoThousandTwentyFiveMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_BorrowingsByNameAxis=ihg_ThreeFiftyMillionPoundTwoPointOneTwoFivePercentageBondsDueInTwoThousandTwentySixMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_BorrowingsByNameAxis=ihg_FiveHundredMillionPoundTwoPointOneTwoFivePercentageBondsDueInTwoThousandTwentySevenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_MeasurementAxis=ifrs-full_AtFairValueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfAssetsAxis=ihg_DerivativeFinancialAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_LevelsOfFairValueHierarchyAxis=ifrs-full_Level1OfFairValueHierarchyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_LevelsOfFairValueHierarchyAxis=ifrs-full_Level2OfFairValueHierarchyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_LevelsOfFairValueHierarchyAxis=ifrs-full_Level3OfFairValueHierarchyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: