XML 97 R90.htm IDEA: XBRL DOCUMENT v3.21.2
Drilling units (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Mar. 31, 2020
Jun. 30, 2021
Jun. 30, 2020
Dec. 31, 2020
Dec. 31, 2019
Cost          
Impairment of long-lived assets   $ (152) $ (1,230)    
Drilling units          
Cost          
Opening balance $ 7,048 3,108 7,048    
Additions   39 85    
Impairment of long-lived assets (1,230) (152) (1,230)    
Closing balance   2,995 5,903    
Accumulated depreciation          
Opening balance $ (647) (988) (647)    
Depreciation   (80) (179)    
Closing balance   (1,068) (826)    
Net book value   $ 1,927 $ 5,077 $ 2,120 $ 6,401