Revenue from contracts with customers - Major Customers (Details) - Contract revenues - Customer concentration risk	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Petrobras
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Customer, Extent of Reliance [Line Items]
Concentration risk percentage	34.00%	37.00%	34.00%	33.00%
Sonadrill
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Customer, Extent of Reliance [Line Items]
Concentration risk percentage	18.00%	21.00%	19.00%	22.00%
Walter Oil & Gas
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Customer, Extent of Reliance [Line Items]
Concentration risk percentage	10.00%	5.00%	10.00%	4.00%
LLOG
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Customer, Extent of Reliance [Line Items]
Concentration risk percentage	9.00%	11.00%	11.00%	9.00%
Talos
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Customer, Extent of Reliance [Line Items]
Concentration risk percentage	1.00%	12.00%	3.00%	13.00%
Other
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Customer, Extent of Reliance [Line Items]
Concentration risk percentage	28.00%	14.00%	23.00%	19.00%