Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2022-12-31 |
As at 2021-12-31 |
As at 2020-12-31 |
|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | |||
| Property, plant and equipment [abstract] | |||
| Property, plant and equipment |
300,000
USD
|
1,000,000
USD
|
— |
| Miscellaneous non-current assets [abstract] | |||
| Other non-current assets |
0
USD
|
600,000
USD
|
— |
| Trade and other current receivables [abstract] | |||
| Current trade receivables |
100,000
USD
|
100,000
USD
|
— |
| Other current receivables |
1,400,000
USD
|
193,700,000
USD
|
— |
| Categories of non-current financial assets [abstract] | |||
| Non-current financial assets at fair value through other comprehensive income [abstract] | |||
| Non-current investments in equity instruments designated at fair value through other comprehensive income |
89,400,000
USD
|
90,300,000
USD
|
— |
| Cash and cash equivalents [abstract] | |||
| Cash and cash equivalents |
18,400,000
USD
|
79,000,000
USD
|
41,900,000
USD
|
| Trade and other current payables [abstract] | |||
| Current trade payables |
200,000
USD
|
200,000
USD
|
— |
| Miscellaneous non-current liabilities [abstract] | |||
| Other non-current liabilities | — |
600,000
USD
|
— |
| Miscellaneous current liabilities [abstract] | |||
| Other current liabilities |
2,100,000
USD
|
2,400,000
USD
|
— |
| Net assets (liabilities) [abstract] | |||
| Assets |
109,800,000
USD
|
365,000,000
USD
|
— |
| Liabilities |
2,400,000
USD
|
13,700,000
USD
|
— |
| Net current assets (liabilities) [abstract] | |||
| Current assets |
19,900,000
USD
|
272,800,000
USD
|
— |
| Current liabilities |
2,300,000
USD
|
2,700,000
USD
|
— |
| Assets less current liabilities [abstract] |