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Summary of Significant Accounting Policies - Goodwill Identified by Segment (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 6,067	$ 6,980
Goodwill acquired and adjusted during period	89	74
Impairment		(972)
Currency translation adjustments	71	(15)
Goodwill, Ending Balance	6,227	6,067
Wellbore Technologies [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	2,874	2,874
Goodwill acquired and adjusted during period	37	4
Currency translation adjustments	45	(4)
Goodwill, Ending Balance	2,956	2,874
Completion & Production Solutions [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	2,058	1,997
Goodwill acquired and adjusted during period	41	70
Currency translation adjustments	23	(9)
Goodwill, Ending Balance	2,122	2,058
Rig Technologies [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	1,135	2,109
Goodwill acquired and adjusted during period	11
Impairment		(972)
Currency translation adjustments	3	(2)
Goodwill, Ending Balance	$ 1,149	$ 1,135

X

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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