Other Financial Information (Noncash Opearting Working Capital (Increase) Decrease) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Financial Information [Abstract]
(Increase) decrease in accounts receivable	$ (89,070)	$ 114,401	$ 119,671
Decrease in inventories	12,216	26,883	(5,171)
(Increase) decrease in prepaid expenses	(17,341)	29,570	149,946
Increase (decrease) in accounts payable and accrued liabilities	(51,769)	(51,439)	(328,078)
Current income tax liabilities	(23,844)	16,999	24,943
Net (increase) decrease in noncash operating working capital	(169,808)	136,414	(38,689)
Cash income taxes paid, net of refunds	129,296	68,076	6,707
Interest paid, net of amounts capitalized of $3,719 in 2018 and $3,338 in 2017	167,750	147,975	127,798
Asset retirement costs capitalized	353,436	8,509	13,690
(Increase) decrease in capital expenditure accrual	(42,467)	99,199	158,885
Interest paid, amounts capitalized	$ 5,258	$ 4,488	$ 4,322

Increase (Decrease) In Capital Expenditure Accrual

No definition available.

Name:	mur_IncreaseDecreaseInCapitalExpenditureAccrual
Namespace Prefix:	mur_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Noncash additions to property, plant and equipment for asset retirement costs capitalized.

+ References

No definition available.

+ Details

Name:	mur_NoncashAssetRetirementObligation
Namespace Prefix:	mur_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Other Financial Information [Abstract]

+ References

No definition available.

+ Details

Name:	mur_OtherFinancialInformationAbstract
Namespace Prefix:	mur_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4297-108586

+ Details

Name:	us-gaap_IncomeTaxesPaidNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The increase (decrease) during the reporting period in the amounts payable to vendors for goods and services received and the amount of obligations and expenses incurred but not paid.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

+ Details

Name:	us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The increase (decrease) during the reporting period in amount due within one year (or one business cycle) from customers for the credit sale of goods and services.

+ References

+ Details

Name:	us-gaap_IncreaseDecreaseInAccountsReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The increase (decrease) during the period in the amount due for taxes based on the reporting entity's earnings or attributable to the entity's income earning process (business presence) within a given jurisdiction.

+ References

+ Details

Name:	us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The increase (decrease) during the reporting period in the aggregate value of all inventory held by the reporting entity, associated with underlying transactions that are classified as operating activities.

+ References

+ Details

Name:	us-gaap_IncreaseDecreaseInInventories
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The increase (decrease) during the reporting period of all assets and liabilities used in operating activities.

+ References

+ Details

Name:	us-gaap_IncreaseDecreaseInOperatingCapital
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The increase (decrease) during the reporting period in the amount of outstanding money paid in advance for goods or services that bring economic benefits for future periods.

+ References

+ Details

Name:	us-gaap_IncreaseDecreaseInPrepaidExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of cash paid during the current period for interest that is capitalized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3213-108585

+ Details

Name:	us-gaap_InterestPaidCapitalized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of cash paid, after deduction of cash paid for capitalized interest, for interest. Includes, but is not limited to, payment to settle zero-coupon bond for accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount.

+ References

+ Details

Name:	us-gaap_InterestPaidNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration