Defined contribution plan contribution rates as a percentage of employees earnings.

No definition available.

Name:	mdr_DefinedContributionPlanContributionRatesAsPercentageOfEmployeesEarnings
Namespace Prefix:	mdr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Defined contribution plan matching percent of compensation.

+ References

No definition available.

+ Details

Name:	mdr_DefinedContributionPlanMatchingPercentOfCompensation
Namespace Prefix:	mdr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

For a classified balance sheet, the amount recognized in balance sheet as a current asset associated with the plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64852052&loc=d3e1703-114919

+ Details

Name:	us-gaap_DefinedBenefitPlanCurrentAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage employer matches of the employee's percentage contribution matched.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=us-gaap_ForeignPensionPlansDefinedBenefitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_CashAndCashEquivalentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Pension and Postretirement Benefits - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
TCN Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions, percentage match of participants' contributions	50.00%
Employer contributions, percentage unmatched of participants' contributions	3.00%
TCN Plan [Member] \| Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan matching percent of compensation	6.00%
TCN Plan [Member] \| Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets held in cash in cash equivalents		$ 14
Domestic Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions, percentage match of participants' contributions	50.00%
Employer contributions, percentage unmatched of participants' contributions	3.00%
Domestic Plans [Member] \| Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan matching percent of compensation	6.00%