Number of newbuilding contracts.

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Revenue From Contract With Customer, Surcharge

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Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

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Amount of receivable related to a loss contingency accrual. For example, an insurance recovery receivable.

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Amount, before deduction of insurance proceeds, of loss recognized in the income statement for an event or transaction that is unusual in nature or infrequent in occurrence, or both.

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Commitments and contingencies (Details) $ in Millions		6 Months Ended
Commitments and contingencies (Details) $ in Millions	Jun. 28, 2019	Jun. 30, 2019 USD ($) rig	Dec. 31, 2018 USD ($)
Guarantor Obligations [Line Items]
Insurance receivable		$ 23	$ 1
Equipment malfunction
Guarantor Obligations [Line Items]
Cost to repair equipment		17
Equipment malfunction \| Physical damage insurance
Guarantor Obligations [Line Items]
Insurance receivable		$ 16
Dalian
Guarantor Obligations [Line Items]
Number of newbuilding contracts \| rig		6
Maximum guarantee			$ 400
Nigeria \| Seadrill Mobile Units (Nigeria) Ltd
Guarantor Obligations [Line Items]
Contract revenue, surcharge	2.00%