Property, Plant and Equipment - Components of Property, Plant and Equipment (Parenthetical) (Detail) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Pipeline equipment [Member]
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ 3,075	$ 2,761
Offshore Drilling Equipment [Member]
Property, Plant and Equipment [Line Items]
Accumulated depreciation	2,885	3,067
Other [Member]
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ 1,114	$ 1,056

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.14)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant