Adjustments to additional paid in capital common stock payable for prepaid service.

No definition available.

Name:	mdr_AdjustmentsToAdditionalPaidInCapitalCommonStockPayableForPrepaidService
Namespace Prefix:	mdr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Bank guarantees outstanding.

+ References

No definition available.

+ Details

Name:	mdr_BankGuaranteesOutstanding
Namespace Prefix:	mdr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt instrument maturity year.

+ References

No definition available.

+ Details

Name:	mdr_DebtInstrumentMaturityYear
Namespace Prefix:	mdr_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	duration

- Definition

Equity investment ownership percentage.

+ References

No definition available.

+ Details

Name:	mdr_EquityInvestmentOwnershipPercentage
Namespace Prefix:	mdr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Excess cash flow percentage.

+ References

No definition available.

+ Details

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

- Definition

Letters of credit surety bonds and other arrangements.

+ References

No definition available.

+ Details

Name:	mdr_LettersOfCreditSuretyBondsAndOtherArrangements
Namespace Prefix:	mdr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line of credit facility aggregate leverage ratio.

+ References

No definition available.

+ Details

Name:	mdr_LineOfCreditFacilityAggregateLeverageRatio
Namespace Prefix:	mdr_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Line of credit facility collateral amount.

+ References

No definition available.

+ Details

Name:	mdr_LineOfCreditFacilityCollateralAmount
Namespace Prefix:	mdr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line of credit facility maximum uncommitted outstanding amount.

+ References

No definition available.

+ Details

Name:	mdr_LineOfCreditFacilityMaximumUncommittedOutstandingAmount
Namespace Prefix:	mdr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Principal amount per amortizing note.

+ References

No definition available.

+ Details

Name:	mdr_PrincipalAmountPerAmortizingNote
Namespace Prefix:	mdr_
Data Type:	us-types:perUnitItemType
Balance Type:	na
Period Type:	instant

- Definition

Purchase agreement period.

+ References

No definition available.

+ Details

Name:	mdr_PurchaseAgreementPeriod
Namespace Prefix:	mdr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Receivables sold.

+ References

No definition available.

+ Details

Name:	mdr_ReceivablesSold
Namespace Prefix:	mdr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Reinvestment period.

+ References

No definition available.

+ Details

Name:	mdr_ReinvestmentPeriod
Namespace Prefix:	mdr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Restricted cash collateral letters of credit.

+ References

No definition available.

+ Details

Name:	mdr_RestrictedCashCollateralLettersOfCredit
Namespace Prefix:	mdr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Settlement shares per tangible unit.

+ References

No definition available.

+ Details

Name:	mdr_SettlementSharesPerTangibleUnit
Namespace Prefix:	mdr_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Stock issued during period shares tangible units.

+ References

No definition available.

+ Details

Name:	mdr_StockIssuedDuringPeriodSharesTangibleUnits
Namespace Prefix:	mdr_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Tangible units interest rate percentage.

+ References

No definition available.

+ Details

Name:	mdr_TangibleUnitsInterestRatePercentage
Namespace Prefix:	mdr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Tangible units stated amount per unit.

+ References

No definition available.

+ Details

Name:	mdr_TangibleUnitsStatedAmountPerUnit
Namespace Prefix:	mdr_
Data Type:	us-types:perUnitItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=65885119&loc=d3e1392-128463

+ Details

Name:	us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

+ References

+ Details

Name:	us-gaap_CommonStockSharesIssued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The average effective interest rate during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
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_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the required periodic payments applied to principal.

+ References

+ Details

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

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum amount borrowed under the credit facility at any time during the period.

+ References

No definition available.

+ Details

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

- Definition

Description of long-term debt arrangements, which are debt arrangements that originally require full repayment more than twelve months after issuance or greater than the normal operating cycle of the company, if longer, and disclosures pertaining to the underlying arrangements, including repayment terms, conversion features, interest rates, restrictions on assets and activities, debt covenants, and other matters important to users of the financial statements. Types of long-term debt arrangements include borrowing under notes payable, bonds payable, debentures, term loans, and other contractual obligations for payment.

+ References

+ Details

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

- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

An amount representing an agreement for an unconditional promise by the maker to pay the Entity (holder) a definite sum of money at a future date more than one year from the balance sheet date, net of any write-downs taken for collection uncertainty on the part of the holder. Such amount may include accrued interest receivable in accordance with the terms of the debt. The debt also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. This amount does not include amounts related to receivables held-for-sale.

+ References

+ Details

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

- Definition

The fair value of notes issued in noncash investing and financing activities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4332-108586

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4313-108586

+ Details

Name:	us-gaap_NotesIssued1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ References

+ Details

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

- Details

Name:	dei_LegalEntityAxis=mdr_JRayMcDermottDeMexicoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=mdr_McDermottInternationalManagementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mdr_SeniorAmortizingNoteDueAprilOneTwoThousandSeventeenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LetterOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mdr_MiddleEasternBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=mdr_TermLoanMember
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_CreditFacilityAxis=mdr_BusinessLineTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mdr_NorthOceanConstructionFinancingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Debt - Additional Information (Detail)	1 Months Ended		3 Months Ended	12 Months Ended
Debt - Additional Information (Detail)	Feb. 28, 2017 USD ($)	Apr. 30, 2014 USD ($) $ / EquityUnits shares	Mar. 31, 2017 USD ($) shares	Dec. 31, 2016 USD ($) shares	Apr. 03, 2017 $ / shares shares	Mar. 31, 2016 shares	Sep. 30, 2010
Debt Instrument [Line Items]
Unamortized debt issuance costs			$ 11,000,000	$ 14,000,000
Excess cash flow			50.00%
Aggregate principal amount of unreimbursed drawings and advances under line of credit facility			5.53
Units issued \| shares		11,500,000
Tangible units interest rate percentage		6.25%
Unit price per share \| $ / EquityUnits		25
Initial principal amount per amortizing note \| $ / EquityUnits		4.1266
Common stock issued to holders of TEU \| shares			251,489,592	249,690,281		248,374,567
Bank guarantees issued			$ 452,000,000	$ 359,000,000
Bonds issued related to JRM Mexico general agreement of indemnity			80,000,000	79,000,000
Line of Credit facility maximum uncommitted outstanding amount			300,000,000
JRM Mexico [Member]
Debt Instrument [Line Items]
Letter of credit, first lien	$ 50,000,000
Amortizing note interest rate percentage	5.75%
Percentage of ownership in the subsidiary	100.00%
Purchase agreement period	364 days
Receivables sold			2,000,000
Loan agreement for equipment financing, term	21 months
Equipment financing amount	$ 47,000,000
Borrowing outstanding			$ 16,000,000
JRM Mexico [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Base rate and applicable margin	4.25%
McDermott International Management [Member]
Debt Instrument [Line Items]
Percentage of ownership in the subsidiary	100.00%
Description of loan agreement			JRM Mexico’s obligations in connection with this equipment financing are guaranteed by McDermott International Management, S. de RL., one of our 100% owned subsidiaries
Subsequent Event [Member]
Debt Instrument [Line Items]
Common stock issued to holders of TEU \| shares					40,800,000
Settlement rate per tangible equity unit \| $ / shares					$ 3.5496
Senior Amortizing Note Due April 1, 2017
Debt Instrument [Line Items]
Debt instrument maturity date		Apr. 01, 2017
Amortizing note interest rate percentage		7.75%
Senior Notes [Member]
Debt Instrument [Line Items]
Issue of second-lien seven-year senior secured notes		$ 500,000,000
Debt instrument interest rate			8.00%
Debt instrument maturity date			May 01, 2021
Issuance of tangible equity units			$ 240,000,000
Minimum [Member]
Debt Instrument [Line Items]
Aggregate principal amount of unreimbursed drawings and advances under line of credit facility			1.75
Letter of Credit Facility [Member]
Debt Instrument [Line Items]
Letter of credit, first lien		400,000,000	$ 450,000,000
Debt instrument maturity year			2019
Line of Credit facility maximum amount outstanding			$ 372,000,000	442,000,000
Cash collateralize letter of credit permitted to deposit, Amount			300,000,000
Letter of credit supported by Cash collateral			15,000,000	$ 16,000,000
Letter of Credit Facility [Member] \| Middle Eastern Bank [Member]
Debt Instrument [Line Items]
Line of Credit facility maximum amount outstanding			$ 625,000,000
Term Loan [Member]
Debt Instrument [Line Items]
Letter of credit, first lien		$ 300,000,000
Debt instrument maturity year			2019
Term Loan amortization amount			$ 750,000,000
Term Loan [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Reinvestment period			365 days
North Ocean 105 [Member] \| Secured Debt [Member] \| North Ocean Construction Financing [Member]
Debt Instrument [Line Items]
Percentage of interest acquired in subsidiary							75.00%
Ownership percentage in Oceanteam ASA's							25.00%