Fair value measurement - Summary of Fair Value Measurement Hierarchy of Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Equity securities available-for-sale:
Equity securities available-for-sale	$ 127	$ 156
Liabilities
Loans and other borrowings	(2,019)	(1,712)
Derivatives		(3)
GBP400m 3.875% bonds 2022 [member]
Liabilities
Loans and other borrowings	(538)	(489)
GBP300m 3.75% bonds 2025 [member]
Liabilities
Loans and other borrowings	(406)	(370)
GBP350m 2.125% bonds 2026 [member]
Liabilities
Loans and other borrowings	(472)	(430)
Finance lease obligations [member]
Liabilities
Loans and other borrowings	(231)	(227)
Fair value [member]
Equity securities available-for-sale:
Equity securities available-for-sale	127	156
Liabilities
Derivatives		(3)
Fair value [member] \| Quoted equity shares [member]
Equity securities available-for-sale:
Equity securities available-for-sale	10	14
Fair value [member] \| Unquoted equity shares [member]
Equity securities available-for-sale:
Equity securities available-for-sale	117	142
Fair value [member] \| GBP400m 3.875% bonds 2022 [member]
Liabilities
Loans and other borrowings	(593)	(541)
Fair value [member] \| GBP300m 3.75% bonds 2025 [member]
Liabilities
Loans and other borrowings	(441)	(408)
Fair value [member] \| GBP350m 2.125% bonds 2026 [member]
Liabilities
Loans and other borrowings	(454)	(411)
Fair value [member] \| Finance lease obligations [member]
Liabilities
Loans and other borrowings	(318)	(297)
Level 1 [member] \| Fair value [member] \| Quoted equity shares [member]
Equity securities available-for-sale:
Equity securities available-for-sale	10	14
Level 1 [member] \| Fair value [member] \| GBP400m 3.875% bonds 2022 [member]
Liabilities
Loans and other borrowings	(593)	(541)
Level 1 [member] \| Fair value [member] \| GBP300m 3.75% bonds 2025 [member]
Liabilities
Loans and other borrowings	(441)	(408)
Level 1 [member] \| Fair value [member] \| GBP350m 2.125% bonds 2026 [member]
Liabilities
Loans and other borrowings	(454)	(411)
Level 2 [member] \| Fair value [member]
Liabilities
Derivatives		(3)
Level 2 [member] \| Fair value [member] \| Finance lease obligations [member]
Liabilities
Loans and other borrowings	(318)	(297)
Level 3 [member] \| Fair value [member] \| Unquoted equity shares [member]
Equity securities available-for-sale:
Equity securities available-for-sale	$ 117	$ 142

No definition available.

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

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2017-01-01
-Paragraph 55
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_55&doctype=Standard
-URIDate 2017-03-09

+ 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 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

- Definition

The amount of non-derivative financial assets that are designated as available for sale or are not classified as (a) loans and receivables; (b) held-to-maturity investments; or (c) financial assets at fair value through profit or loss. [Refer: Derivative financial assets; Financial assets at fair value through profit or loss; Held-to-maturity investments]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2018-01-01
-Name IFRS
-Number 7
-IssueDate 2017-01-01
-Paragraph 8
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2017-03-02&anchor=para_8_d&doctype=Standard&book=B
-URIDate 2017-03-09

+ Details

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

- 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_FinanceLeaseObligationsMember
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_CategoriesOfFinancialAssetsAxis=ihg_QuotedEquitySharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_CategoriesOfFinancialAssetsAxis=ihg_UnquotedEquitySharesMember
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: