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Summary of Significant Accounting Policies - Identified Intangible Assets Identified by Segment (Detail) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016
Intangible Asset Excluding Goodwill [Line Items] |  |
Beginning Balance | $ 3,530 | $ 3,849
Additions to intangible assets | 61 | 24
Amortization | (339) | (333)
Currency translation adjustments | 49 | (10)
Ending Balance | 3,301 | 3,530
Wellbore Technologies [Member] |  |
Intangible Asset Excluding Goodwill [Line Items] |  |
Beginning Balance | 2,064 | 2,254
Additions to intangible assets | 18 | 15
Amortization | (208) | (205)
Currency translation adjustments | 9 |
Ending Balance | 1,883 | 2,064
Completion & Production Solutions [Member] |  |
Intangible Asset Excluding Goodwill [Line Items] |  |
Beginning Balance | 1,191 | 1,296
Additions to intangible assets | 41 | 9
Amortization | (108) | (106)
Currency translation adjustments | 36 | (8)
Ending Balance | 1,160 | 1,191
Rig Technologies [Member] |  |
Intangible Asset Excluding Goodwill [Line Items] |  |
Beginning Balance | 275 | 299
Additions to intangible assets | 2 |
Amortization | (23) | (22)
Currency translation adjustments | 4 | (2)
Ending Balance | $ 258 | $ 275

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- Definition The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
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- Definition Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16212-109274 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph ((a)(1),(b)) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
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