Assets Held For Sale and Discontinued Operations - Summary of Discontinued Operations (Parenthetical) (Detail) € in Millions	12 Months Ended
Dec. 31, 2017 EUR (€)
Disclosure of Discontinued Operations [abstract]
Non-cash deferred tax credit	€ 7

Non cash deferred tax credit related to enactment of tax cuts and jobs act.

No definition available.

Name:	crh_NonCashDeferredTaxCreditRelatedToEnactmentOfTaxCutsAndJobsAct
Namespace Prefix:	crh_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration