Business Segments and Geographic Areas - Revenues by Country Based on Sales Destination of Products or Services (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 6,090	$ 8,479	$ 8,453
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	1,634	3,112	3,480
Norway [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	464	512	368
Saudi Arabia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	343	436	444
China [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	288	285	231
Singapore [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	242	473	321
Brazil [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	224	269	415
United Kingdom [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	222	333	309
United Arab Emirates [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	221	224	248
Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	168	247	302
South Korea [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	33	69	169
Other Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 2,251	$ 2,519	$ 2,166