Auditor's Remuneration Paid to Ernst & Young LLP - Summary of Auditor's Remuneration Paid (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Auditor's remuneration [abstract]
Audit fees for specific procedures performed in relation to the implementation of new accounting standards	$ 0.4	$ 0.5	$ 0.0

Audit fees for specific procedures performed in relation to the implementation of new accounting standards.

No definition available.

Name:	ihg_AuditFeesForSpecificProceduresPerformedInRelationToTheImplementationOfNewAccountingStandards
Namespace Prefix:	ihg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration