Allocated share based compensation income expense.

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- Definition

Number of installments payable.

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Option to sell interest in subsidiary acquired by third party.

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Percentage of ownership interest in subsidiary acquired by third party.

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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.

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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- Definition

Number of shares of equity interests issued or issuable to acquire entity.

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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The amount of liability arising from an inherited contingency (as defined) which has been recognized as of the acquisition date.

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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Number of non-vested options outstanding.

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Stockholders' Equity and Equity-Based Incentive Plans - Additional Information (Detail) shares in Millions, $ in Millions		1 Months Ended	3 Months Ended			9 Months Ended		12 Months Ended
	May 10, 2018 USD ($) shares	Jan. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($) shares	Dec. 31, 2002 USD ($) Installment
Accumulated Other Comprehensive Income Loss [Line Items]
Business combination, number of McDermott's shares entitled for each share of CB&I owned \| shares							85.0
Allocated share based compensation (income) expense			$ (3)	$ 1		$ 2	$ 6
P.T. Sarana Interfab Mandiri [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Percentage of participating interest acquired in subsidiary								25.00%
Option to sell interest								$ 5
SG&A [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Stock-based compensation expense			5	$ 9		16	$ 24
Chicago Bridge & Iron Company N.V. [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Business combination, number of McDermott's shares entitled for each share of CB&I owned \| shares	84.5
Business combination, Consideration	$ 2,870
Payment during period	$ 4,565
Chicago Bridge & Iron Company N.V. [Member] \| Restructuring and Integration Costs [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Stock-based compensation expense					$ 26
Chicago Bridge & Iron Company N.V. [Member] \| Restricted Stock Units [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Stock-settled equity-based awards, restricted stock units, unvested \| shares	2.1
Chicago Bridge & Iron Company N.V. [Member] \| Restricted Stock Units [Member] \| Minimum [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Stock-settled equity-based awards, restricted stock units, vesting period	3 years
Chicago Bridge & Iron Company N.V. [Member] \| Restricted Stock Units [Member] \| Maximum [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Stock-settled equity-based awards, restricted stock units, vesting period	4 years
Chicago Bridge & Iron Company N.V. [Member] \| Stock Options [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Stock-settled equity-based awards, stock options, unvested \| shares	0.1
PT McDermott Indonesia [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Business combination, Consideration		$ 29
Number of installments payable \| Installment								2
Payment during period						15
Remaining liability			$ 14			$ 14