Leases (Narrative) (Details)	3 Months Ended
Mar. 31, 2019
Minimum [Member]
Remaining lease terms	1 year
Period in which leases have termination option	1 month
Maximum [Member]
Remaining lease terms	17 years

Operating And Finance Lease Terms, Period In Which Leases Have Termination Option

No definition available.

Name:	mur_OperatingAndFinanceLeaseTermsPeriodInWhichLeasesHaveTerminationOption
Namespace Prefix:	mur_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration