Significant accounting policies - Internal credit risk grades (Details)	Dec. 31, 2021
IFRS Statement [Line Items]
Discount rate for present value of the cash flows	10.00%
Stage 1 \| Aaa – Ba1 \| 1 - 4
IFRS Statement [Line Items]
Percentage of credit loss rate	0.09%
Stage 1 \| Ba2 – B3 \| 5 - 6
IFRS Statement [Line Items]
Percentage of credit loss rate	2.28%
Stage 1 \| Caa1 - Caa3 \| 7
IFRS Statement [Line Items]
Percentage of credit loss rate	7.81%
Stage 1 \| Ca \| 8 - 9
IFRS Statement [Line Items]
Percentage of credit loss rate	34.52%
Stage 1 \| C \| 10
IFRS Statement [Line Items]
Percentage of credit loss rate	100.00%

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- Definition

The discount rate applied to cash flow projections for a cash-generating unit (group of units). [Refer: Cash-generating units [member]]

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- Definition

The rate of expected credit losses, calculated as percentage of the gross carrying amount. Expected credit losses are the weighted average of credit losses with the respective risks of a default occurring as the weights.

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