Asset Impairments - Additional Information (Detail) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2020 USD ($)	Mar. 31, 2020 USD ($) $ / Barrel	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Indefinite Lived Intangible Assets By Major Class [Line Items]
Decrease in oil price per barrel | $ / Barrel		40
Impairment charge on goodwill	$ 0	$ 1,295	$ 1,295	$ 3,509
Impairment of intangible assets, indefinite-lived (excluding goodwill)		83
Goodwill	1,493		$ 1,493	2,807	$ 6,264
Impairment on equity investment		224
Impairment of Intangible Assets, Finite-lived		209
Impairment of property, plant and equipment		262
Impairment of right-of-use assets		$ 42
Estimated useful lives of intangible assets, minimum			2 years
Estimated useful lives of intangible assets, maximum			30 years
Amortization expense, 2020	43		$ 43
Amortization expense, 2021	40		40
Amortization expense, 2022	33		33
Amortization expense, 2023	28		28
Amortization expense, 2024	25		25
Intangibles, net	527		527	$ 852
Rig Equipment [Member]
Indefinite Lived Intangible Assets By Major Class [Line Items]
Goodwill	661		661
Marine Construction [Member]
Indefinite Lived Intangible Assets By Major Class [Line Items]
Goodwill	51		51
ReedHycalog [Member]
Indefinite Lived Intangible Assets By Major Class [Line Items]
Goodwill	124		124
WellSite Services [Member]
Indefinite Lived Intangible Assets By Major Class [Line Items]
Goodwill	174		174
XL Systems [Member]
Indefinite Lived Intangible Assets By Major Class [Line Items]
Goodwill	64		64
M/D Totco [Member]
Indefinite Lived Intangible Assets By Major Class [Line Items]
Goodwill	10		10
PFT [Member]
Indefinite Lived Intangible Assets By Major Class [Line Items]
Goodwill	41		41
Fiberglass Systems [Member]
Indefinite Lived Intangible Assets By Major Class [Line Items]
Goodwill	346		346
Industrial [Member]
Indefinite Lived Intangible Assets By Major Class [Line Items]
Goodwill	$ 22		$ 22