Lease Obligations - Additional Information (Detail) - USD ($) $ in Millions	Jul. 27, 2018	Dec. 31, 2019	Dec. 31, 2018
Lessee Lease Description [Line Items]
Finance lease liability		$ 47
Finance lease assets		50	$ 70
Jack-up Barge [Member]
Lessee Lease Description [Line Items]
Finance lease assets			17
Amazon Pipe-lay and Construction Vessel [Member]
Lessee Lease Description [Line Items]
Capital expenditure expected	$ 58
Property, plant and equipment, net		49	52
Accumulated amortization,net		6	3
Finance lease liability		$ 46	$ 53
Amazon Pipe-lay and Construction Vessel [Member] | Minimum [Member]
Lessee Lease Description [Line Items]
Cost of modification including project management and other fees and expenses	260
Amazon Pipe-lay and Construction Vessel [Member] | Maximum [Member]
Lessee Lease Description [Line Items]
Cost of modification including project management and other fees and expenses	$ 290