Segment Reporting - Operating Information by Segment (Parenthetical) (Detail) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2018		Sep. 30, 2018		Jun. 30, 2018		Mar. 31, 2018		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Transaction costs	$ 3,000,000	[1]	$ 5,000,000	[1]	$ 37,000,000	[1]	$ 3,000,000	[1]	$ 48,000,000	$ 9,000,000
Restructuring and integration costs	28,000,000	[2]	$ 31,000,000	[2]	$ 63,000,000	[2]	$ 12,000,000	[2]	134,000,000	0	$ 11,000,000
Impairment charges	58,000,000	[3]							58,000,000	1,000,000	55,000,000
Accrued and unpaid capital expenditures reported in PP&E and accrued liabilities	26,000,000								26,000,000	8,000,000	8,000,000
Receivables from unconsolidated affiliates	$ 15,000,000								15,000,000	$ 7,000,000
Amazon Pipe-lay and Construction Vessel [Member]
Segment Reporting Information [Line Items]
Bareboat charter agreement, term										11 years
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Transaction costs									48,000,000	$ 9,000,000
Restructuring and integration costs									134,000,000
Impairment charges									58,000,000		55,000,000
Alternate Arrangement Expenses									$ 25,000,000
Gain on sale of assets										$ 4,000,000
Restructuring expenses											$ 11,000,000

[1] Transaction costs relate to professional service fees (including audit, legal and advisory services) associated with the Combination. See Note 3, Business Combination, for further discussion.

[2] Restructuring and integration costs primarily relate to costs to achieve our CPI. See Note 12, Restructuring and Integration Costs, for further discussion.

[3] Represents charges associated with the impairment of two vessels within our Corporate operating group, due to changes in their level of planned utilization during 2018. See Note 16, Fair Value Measurements, for further discussion.