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Decommissioning and Other Provisions (Tables) | 12 Months Ended
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Dec. 31, 2021
Other Provisions, Contingent Liabilities And Contingent Assets [Abstract] |
Change in decommissioning and other provision balances | The change in decommissioning and other provision balances is as follows:
| Decommissioning and restoration | Other provisions | Total
Balance, Dec. 31, 2019 | 501 |  | 45 |  | 546 |
Liabilities incurred | 1 |  | 34 |  | 35 |
Liabilities settled | (18) |  | (19) |  | (37) |
Accretion | 30 |  | — |  | 30 |
Acquisition of liabilities | 1 |  | — |  | 1 |
Revisions in estimated cash flows | 61 |  | 11 |  | 72 |
Revisions in discount rates(1) | 36 |  | — |  | 36 |
Reversals | — |  | (6) |  | (6) |
Change in foreign exchange rates | (4) |  | — |  | (4) |
Balance, Dec. 31, 2020 | 608 |  | 65 |  | 673 |
Liabilities incurred | 8 |  | 22 |  | 30 |
Liabilities settled (Note 36) | (18) |  | (62) |  | (80) |
Accretion | 32 |  | — |  | 32 |
Acquisition of liabilities | 2 |  | — |  | 2 |
Revisions in estimated cash flows | 167 |  | 12 |  | 179 |
Revisions in discount rates | (6) |  | — |  | (6) |
Reversals | — |  | (3) |  | (3) |
Balance, Dec. 31, 2021 | 793 |  | 34 |  | 827 |
(1) Discount rates at Dec. 31, 2020, are generally lower than those at Dec. 31, 2019, due to decreases in the underlying risk-free US and Canadian benchmark yields and changes in credit spreads due to volatility within the market as a result of COVID-19. On average, these rates decreased by approximately 0.3 to 0.9 per cent.
| Decommissioning and restoration | Other | Total
Balance, Dec. 31, 2020 | 608 |  | 65 |  | 673 |
Current portion | 21 |  | 38 |  | 59 |
Non-current portion | 587 |  | 27 |  | 614 |
Balance, Dec. 31, 2021 | 793 |  | 34 |  | 827 |
Current portion | 35 |  | 13 |  | 48 |
Non-current portion | 758 |  | 21 |  | 779 |

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- Definition The disclosure of other provisions. [Refer: Other provisions] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 37 -IssueDate 2021-01-01 -Paragraph 84 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=37&code=ifrs-tx-2021-en-r&anchor=para_84&doctype=Standard -URIDate 2021-03-24 + Details
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