Employee Future Benefits - Major Categories of Plan Assets and Actual Percent Allocation (Detail) - CAD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023
Pension plans
Disclosure of fair value of plan assets [Line Items]
Total	$ 3,820.0	$ 3,706.0
Retiree welfare plans
Disclosure of fair value of plan assets [Line Items]
Total	553.0	526.0
U.S. plans
Disclosure of fair value of plan assets [Line Items]
Public equity securities	$ 2.1	$ 1.4
Percentage of plan assets	16.00%	16.00%
U.S. plans \| Pension plans
Disclosure of fair value of plan assets [Line Items]
Total	$ 2,635.0	$ 2,521.0
Percentage of fair value measurements	100.00%	100.00%
U.S. plans \| Pension plans \| Cash and cash equivalents
Disclosure of fair value of plan assets [Line Items]
Cash and cash equivalents	$ 35.0	$ 28.0
Percentage of fair value measurements	1.00%	1.00%
U.S. plans \| Pension plans \| Public equities
Disclosure of fair value of plan assets [Line Items]
Public equity securities	$ 346.0	$ 315.0
Percentage of fair value measurements	14.00%	13.00%
U.S. plans \| Pension plans \| Debt securities
Disclosure of fair value of plan assets [Line Items]
Public debt securities	$ 1,513.0	$ 1,437.0
Percentage of fair value measurements	57.00%	57.00%
U.S. plans \| Pension plans \| Other invested assets
Disclosure of fair value of plan assets [Line Items]
Other investments	$ 741.0	$ 741.0
Percentage of fair value measurements	28.00%	29.00%
U.S. plans \| Retiree welfare plans
Disclosure of fair value of plan assets [Line Items]
Total	$ 553.0	$ 526.0
Percentage of fair value measurements	100.00%	100.00%
U.S. plans \| Retiree welfare plans \| Cash and cash equivalents
Disclosure of fair value of plan assets [Line Items]
Cash and cash equivalents	$ 23.0	$ 25.0
Percentage of fair value measurements	4.00%	5.00%
U.S. plans \| Retiree welfare plans \| Public equities
Disclosure of fair value of plan assets [Line Items]
Public equity securities	$ 41.0	$ 39.0
Percentage of fair value measurements	7.00%	7.00%
U.S. plans \| Retiree welfare plans \| Debt securities
Disclosure of fair value of plan assets [Line Items]
Public debt securities	$ 476.0	$ 448.0
Percentage of fair value measurements	87.00%	85.00%
U.S. plans \| Retiree welfare plans \| Other invested assets
Disclosure of fair value of plan assets [Line Items]
Other investments	$ 13.0	$ 14.0
Percentage of fair value measurements	2.00%	3.00%
Canadian plans
Disclosure of fair value of plan assets [Line Items]
Percentage of plan assets	0.10%	0.10%
Canadian plans \| Pension plans
Disclosure of fair value of plan assets [Line Items]
Total	$ 1,185.0	$ 1,185.0
Percentage of fair value measurements	100.00%	100.00%
Canadian plans \| Pension plans \| Cash and cash equivalents
Disclosure of fair value of plan assets [Line Items]
Cash and cash equivalents	$ 11.0	$ 15.0
Percentage of fair value measurements	1.00%	1.00%
Canadian plans \| Pension plans \| Public equities
Disclosure of fair value of plan assets [Line Items]
Public equity securities	$ 205.0	$ 195.0
Percentage of fair value measurements	17.00%	17.00%
Canadian plans \| Pension plans \| Debt securities
Disclosure of fair value of plan assets [Line Items]
Public debt securities	$ 968.0	$ 974.0
Percentage of fair value measurements	82.00%	82.00%
Canadian plans \| Pension plans \| Other invested assets
Disclosure of fair value of plan assets [Line Items]
Other investments	$ 1.0	$ 1.0
Percentage of fair value measurements	0.00%	0.00%
Canadian plans \| Retiree welfare plans
Disclosure of fair value of plan assets [Line Items]
Total	$ 0.0	$ 0.0
Percentage of fair value measurements	0.00%	0.00%
Canadian plans \| Retiree welfare plans \| Cash and cash equivalents
Disclosure of fair value of plan assets [Line Items]
Cash and cash equivalents	$ 0.0	$ 0.0
Percentage of fair value measurements	0.00%	0.00%
Canadian plans \| Retiree welfare plans \| Public equities
Disclosure of fair value of plan assets [Line Items]
Public equity securities	$ 0.0	$ 0.0
Percentage of fair value measurements	0.00%	0.00%
Canadian plans \| Retiree welfare plans \| Debt securities
Disclosure of fair value of plan assets [Line Items]
Public debt securities	$ 0.0	$ 0.0
Percentage of fair value measurements	0.00%	0.00%
Canadian plans \| Retiree welfare plans \| Other invested assets
Disclosure of fair value of plan assets [Line Items]
Other investments	$ 0.0	$ 0.0
Percentage of fair value measurements	0.00%	0.00%

The amount cash and cash equivalents contribute to the fair value of defined benefit plan assets. [Refer: Cash and cash equivalents; Plan assets, at fair value; Defined benefit plans [domain]]

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 19
-IssueDate 2024-01-01
-Paragraph 142
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2024-en-r&anchor=para_142_a&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_CashAndCashEquivalentsAmountContributedToFairValueOfPlanAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount instruments representing debt (rather than equity) contribute to the fair value of defined benefit plan assets. [Refer: Plan assets, at fair value; Defined benefit plans [domain]]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 19
-IssueDate 2024-01-01
-Paragraph 142
-Subparagraph c
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2024-en-r&anchor=para_142_c&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_DebtInstrumentsAmountContributedToFairValueOfPlanAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

Name:	ifrs-full_DisclosureOfFairValueOfPlanAssetsLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount instruments representing equity (rather than debt) contribute to the fair value of defined benefit plan assets. [Refer: Plan assets, at fair value; Defined benefit plans [domain]]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 19
-IssueDate 2024-01-01
-Paragraph 142
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2024-en-r&anchor=para_142_b&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_EquityInstrumentsAmountContributedToFairValueOfPlanAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount other types of assets not separately disclosed contribute to the fair value of defined benefit plan assets. [Refer: Plan assets, at fair value; Defined benefit plans [domain]]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2024-01-01
-Paragraph 142
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2024-en-r&anchor=para_142&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_OtherAssetsAmountContributedToFairValueOfPlanAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The fair value of defined benefit plan assets. Plan assets comprise assets held by a long-term employee benefit fund and qualifying insurance policies. [Refer: At fair value [member]]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2024-01-01
-Paragraph 57
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2024-en-r&anchor=para_57_a&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_PlanAssetsAtFairValue
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Defined Benefit Plan Target Asset Allocation Percentage

+ References

No definition available.

+ Details

Name:	mfc_DefinedBenefitPlanTargetAssetAllocationPercentage
Namespace Prefix:	mfc_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage Of Plan Assets Not Quoted In Active Markets

+ References

No definition available.

+ Details

Name:	mfc_PercentageOfPlanAssetsNotQuotedInActiveMarkets
Namespace Prefix:	mfc_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	ifrs-full_DefinedBenefitPlansAxis=ifrs-full_PensionDefinedBenefitPlansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_DefinedBenefitPlansAxis=mfc_RetireeWelfarePlansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ActuarialAssumptionsAxis=mfc_USPlansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfFinancialInstrumentsAxis=mfc_CashCashAndCashEquivalentsAndCurrentAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfFinancialInstrumentsAxis=mfc_PublicEquitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfFinancialInstrumentsAxis=ifrs-full_DebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfFinancialInstrumentsAxis=mfc_OtherInvestedAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ActuarialAssumptionsAxis=mfc_CanadianPlansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: