Related party transactions - Summary of Average Bareboat Charter Rates per Day (Details) $ in Thousands	Dec. 31, 2020 USD ($)
West Taurus
Sale Leaseback Transaction [Line Items]
2021	$ 96
2022	96
2023	181
2024	177
2025 and thereafter	0
West Hercules
Sale Leaseback Transaction [Line Items]
2021	96
2022	96
2023	183
2024	176
2025 and thereafter	0
West Linus
Sale Leaseback Transaction [Line Items]
2021	99
2022	92
2023	189
2024	153
2025 and thereafter	$ 122

- Definition

The average bareboat charter rate per day based on the Base LIBOR Interest Rate for the fifth fiscal year following the latest fiscal year.

+ References

No definition available.

+ Details

Name:	sdrl_BareboatCharterRatePerDayAverageYearFiveAndThereafter
Namespace Prefix:	sdrl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The average bareboat charter rate per day based on the Base LIBOR Interest Rate for the fourth fiscal year following the latest fiscal year.

+ References

No definition available.

+ Details

Name:	sdrl_Bareboatcharterrateperdayaverageyearfour
Namespace Prefix:	sdrl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The average bareboat charter rate per day based on the Base LIBOR Interest Rate for the first fiscal year following the latest fiscal year.

+ References

No definition available.

+ Details

Name:	sdrl_Bareboatcharterrateperdayaverageyearone
Namespace Prefix:	sdrl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The average bareboat charter rate per day based on the Base LIBOR Interest Rate for the third fiscal year following the latest fiscal year.

+ References

No definition available.

+ Details

Name:	sdrl_Bareboatcharterrateperdayaverageyearthree
Namespace Prefix:	sdrl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The average bareboat charter rate per day based on the Base LIBOR Interest Rate for the second fiscal year following the latest fiscal year.

+ References

No definition available.

+ Details

Name:	sdrl_Bareboatcharterrateperdayaverageyeartwo
Namespace Prefix:	sdrl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_SaleLeasebackTransactionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_SaleLeasebackTransactionDescriptionAxis=sdrl_WestTaurusMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SaleLeasebackTransactionDescriptionAxis=sdrl_WestHerculesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SaleLeasebackTransactionDescriptionAxis=sdrl_WestLinusMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: