XML 95 R61.htm IDEA: XBRL DOCUMENT
v3.22.1

Share Capital (Share Capital) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020
Reconciliation of number of shares outstanding [abstract] |  |
Beginning balance | $ 2,851.5 |
Shares issued through: |  |
Ending balance | $ 2,735.6 | $ 2,851.5
Issued capital [member] |  |
Reconciliation of number of shares outstanding [abstract] |  |
Number of shares outstanding | 392,776,822 | 391,070,817
Beginning balance | $ 3,702.9 | $ 3,693.3
Shares issued through: |  |
Share-based employment compensation plans (in shares) | 40,000 | 1,653,361
Share-based compensation plans | $ 0.3 | $ 10.3
Shares repurchased and cancelled (in shares) | (1,583,562) | (1,133,561)
Shares repurchased and cancelled |  | $ (10.7)
Dividend reinvestment plan and share purchase plan (in shares) | 656,473 | 1,186,205
Dividend reinvestment plan (ii) | $ 4.6 | $ 10.0
Number of shares outstanding | 391,889,733 | 392,776,822
Ending balance | $ 3,692.9 | $ 3,702.9

X
- Definition Number of Shares Issued Through DRIP + References No definition available. + Details
Name: | agi_NumberOfSharesIssuedThroughDRIP
Namespace Prefix: | agi_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of Shares Issued Through Share-Based Employment Compensation Plans + References No definition available. + Details
Name: | agi_NumberofSharesIssuedThroughShareBasedEmploymentCompensationPlans
Namespace Prefix: | agi_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Stock Issued During Period, Value, DRIP + References No definition available. + Details
Name: | agi_StockIssuedDuringPeriodValueDRIP
Namespace Prefix: | agi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Stock Issued During Period, Value, Employee Stock Purchase Plan1 + References No definition available. + Details
Name: | agi_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan1
Namespace Prefix: | agi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Stock Repurchased and Cancellation During Period, Value + References No definition available. + Details
Name: | agi_StockRepurchasedandCancellationDuringPeriodValue
Namespace Prefix: | agi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of residual interest in the assets of the entity after deducting all its liabilities. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 1 -IssueDate 2021-01-01 -Paragraph 24 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2021-en-r&anchor=para_24_a&doctype=Standard -URIDate 2021-03-24 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 1 -IssueDate 2021-01-01 -Paragraph 32 -Subparagraph a -Clause i -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2021-en-r&anchor=para_32_a_i&doctype=Standard -URIDate 2021-03-24 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 13 -IssueDate 2021-01-01 -Paragraph 93 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2021-en-r&anchor=para_93_a&doctype=Standard -URIDate 2021-03-24 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 13 -IssueDate 2021-01-01 -Paragraph 93 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2021-en-r&anchor=para_93_b&doctype=Standard -URIDate 2021-03-24 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 13 -IssueDate 2021-01-01 -Paragraph 93 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2021-en-r&anchor=para_93_e&doctype=Standard -URIDate 2021-03-24 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2021-01-01 -Paragraph 55 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_55&doctype=Standard -URIDate 2021-03-24 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2021-01-01 -Paragraph 78 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_78_e&doctype=Standard -URIDate 2021-03-24 + Details
Name: | ifrs-full_Equity
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The increase (decrease) in the number of ordinary shares issued. [Refer: Ordinary shares [member]] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2021-01-01 -Paragraph 112 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_112_c&doctype=Standard -URIDate 2021-03-24 + Details
Name: | ifrs-full_IncreaseDecreaseInNumberOfOrdinarySharesIssued
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | ifrs-full_NumberOfSharesIssuedAbstract
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of shares that have been authorised and issued, reduced by treasury shares held. [Refer: Treasury shares] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2021-01-01 -Paragraph 79 -Subparagraph a -Clause iv -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_79_a_iv&doctype=Standard -URIDate 2021-03-24 + Details
Name: | ifrs-full_NumberOfSharesOutstanding
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- References No definition available. + Details
Name: | ifrs-full_ReconciliationOfNumberOfSharesOutstandingAbstract
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | ifrs-full_ComponentsOfEquityAxis=ifrs-full_IssuedCapitalMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |