XML 124 R90.htm IDEA: XBRL DOCUMENT
v3.22.1

Management of Capital (Details) - USD ($) $ in Millions | Dec. 31, 2021 | Dec. 31, 2020
--- | --- | ---
Disclosure of objectives, policies and processes for managing capital [abstract] |  |
Shareholder's equity | $ 2,735.6 | $ 2,851.5
Managed capital |  | $ 2,851.5

X
- Definition Managed Capital, Equity, Debt and Financing Obligations + References No definition available. + Details
Name: | agi_ManagedCapitalEquityDebtandFinancingObligations
Namespace Prefix: | agi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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