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Property, plant and equipment - Key Assumptions (Details) - Titian CGU	Dec. 31, 2020
Disclosure of detailed information about property, plant and equipment [line items]
Discount rate used in current estimate of value in use	13.00%
Long-term average realized price
Disclosure of detailed information about property, plant and equipment [line items]
Change Required for Carrying Value to Equal Recoverable Value	0.03
Production volumes
Disclosure of detailed information about property, plant and equipment [line items]
Change Required for Carrying Value to Equal Recoverable Value	0.11
Gas price
Disclosure of detailed information about property, plant and equipment [line items]
Change Required for Carrying Value to Equal Recoverable Value	0.07
Discount rate (after-tax)
Disclosure of detailed information about property, plant and equipment [line items]
Change Required for Carrying Value to Equal Recoverable Value	0.0330

X

- Definition

The amount by which value that has been assigned to a key assumption must change in order for a unit's recoverable amount to be equal to its carrying amount. [Refer: Carrying amount [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-IssueDate 2020-01-01
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

The discount rate used in the current estimate of the present value of the future cash flows expected to be derived from an asset or cash-generating unit.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
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-IssueDate 2020-01-01
-Paragraph 130
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- Definition

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

+ References

No definition available.

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