Goodwill (Details) $ / shares in Units, $ in Millions	9 Months Ended
Sep. 30, 2018 USD ($) item $ / shares
Goodwill
Number of impaired ultra-deepwater floaters \| item	3
Loss on impairment of goodwill	$ 462
Loss on impairment of goodwill per diluted share from continuing operations \| $ / shares	$ 1.02
Loss on impairment of goodwill, tax effect	$ 0

Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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