Other liabilities - Future amortization of unfavorable contracts (Details) - Unfavorable contracts - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other Liabilities [Line Items]
Weighted average remaining amortization period	7 years 9 months
2019	$ (1)
2020	(1)
2021	(1)
2022	(1)
2023 and after	(4)
Total	$ (8)	$ (27)	$ (66)

Finite-Lived Intangible Liabilities, Amortization Expense, Next Twelve Months

No definition available.

Name:	sdrl_FiniteLivedIntangibleLiabilitiesAmortizationExpenseNextTwelveMonths
Namespace Prefix:	sdrl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Finite-Lived Intangible Liabilities, Amortization Expense, Year Five and Thereafter

No definition available.

Name:	sdrl_FiniteLivedIntangibleLiabilitiesAmortizationExpenseYearFiveandThereafter
Namespace Prefix:	sdrl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Finite-Lived Intangible Liabilities, Amortization Expense, Year Four

No definition available.

Name:	sdrl_FiniteLivedIntangibleLiabilitiesAmortizationExpenseYearFour
Namespace Prefix:	sdrl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Finite-Lived Intangible Liabilities, Amortization Expense, Year Three

No definition available.

Name:	sdrl_FiniteLivedIntangibleLiabilitiesAmortizationExpenseYearThree
Namespace Prefix:	sdrl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Finite-Lived Intangible Liabilities, Amortization Expense, Year Two

No definition available.

Name:	sdrl_FiniteLivedIntangibleLiabilitiesAmortizationExpenseYearTwo
Namespace Prefix:	sdrl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Finite-Lived Intangible Liabilities, Net

No definition available.

Name:	sdrl_FiniteLivedIntangibleLiabilitiesNet
Namespace Prefix:	sdrl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Finite-Lived Intangible Liabilities, Remaining Amortization Period

No definition available.

Name:	sdrl_FiniteLivedIntangibleLiabilitiesRemainingAmortizationPeriod
Namespace Prefix:	sdrl_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

[Line Items] for Other Liabilities [Table]

No definition available.

Name:	sdrl_OtherLiabilitiesLineItems
Namespace Prefix:	sdrl_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Name:	us-gaap_FairValueByLiabilityClassAxis=sdrl_UnfavorableContractsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: