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Assets Held For Sale - Additional Information (Detail) - USD ($) $ in Millions | 6 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | ---
Jun. 30, 2017 | Dec. 31, 2017 | Jun. 30, 2018 | May 09, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |
Investment owned (as percent) |  |  | 23.00% |
Loss on disposals | $ 166 |  |  |
Drilling Unit [Member] | Sale of West Rige [Member] |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |
Loss on disposals |  | $ (2) |  |
Jurong Shipyard [Member] |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |
Investment owned (as percent) |  |  | 77.00% |
Jurong Shipyard [Member] | Drilling Unit [Member] | Sale of West Rige [Member] |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |
Fair value of consideration received |  |  |  | $ 126

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