The amount of assets that are: (a) cash; (b) an equity instrument of another entity; (c) a contractual right: (i) to receive cash or another financial asset from another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially favourable to the entity; or (d) a contract that will, or may be, settled in the entity’s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to receive a variable number of the entity’s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity’s own equity instruments. For this purpose the entity’s own equity instruments do not include puttable financial instruments classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity’s own equity instruments. [Refer: Financial instruments, class [member]; Financial liabilities]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2023-01-01
-Paragraph 25
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2023-en-r&anchor=para_25&doctype=Standard
-URIDate 2023-03-23

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2023-01-01
-Paragraph 35H
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2023-en-r&anchor=para_35H&doctype=Standard
-URIDate 2023-03-23

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2023-01-01
-Paragraph 35M
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2023-en-r&anchor=para_35M&doctype=Standard
-URIDate 2023-03-23

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Name IFRS
-Number 7
-IssueDate 2023-01-01
-Paragraph 35N
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2023-en-r&anchor=para_35N&doctype=Standard
-URIDate 2023-03-23

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2023-01-01
-Paragraph 35I
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2023-en-r&anchor=para_35I&doctype=Standard
-URIDate 2023-03-23

+ Details

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

- Definition

The fair value of financial assets. [Refer: At fair value [member]; Financial assets]

+ References

+ Details

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

- Definition

The amount of liabilities that are: (a) a contractual obligation: (i) to deliver cash or another financial asset to another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially unfavourable to the entity; or (b) a contract that will, or may be, settled in the entity’s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to deliver a variable number of the entity’s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity’s own equity instruments. For this purpose, rights, options or warrants to acquire a fixed number of the entity’s own equity instruments for a fixed amount of any currency are equity instruments if the entity offers the rights, options or warrants pro rata to all of its existing owners of the same class of its own non-derivative equity instruments. Also, for those purposes the entity’s own equity instruments do not include puttable financial instruments that are classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity’s own equity instruments. As an exception, an instrument that meets the definition of a financial liability is classified as an equity instrument if it has all the features and meets the conditions in paragraphs 16A-16B or paragraphs 16C-16D of IAS 32. [Refer: Financial instruments, class [member]; Financial assets; Derivatives [member]]

+ References

+ Details

Name:	ifrs-full_FinancialLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fair value of financial liabilities. [Refer: At fair value [member]; Financial liabilities]

+ References

+ Details

Name:	ifrs-full_FinancialLiabilitiesAtFairValue
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The gross amount of recognised financial liabilities that are subject either to offsetting or to an enforceable master netting arrangement or similar agreement. [Refer: Financial liabilities]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2023-01-01
-Paragraph 13C
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2023-en-r&anchor=para_13C_a&doctype=Standard
-URIDate 2023-03-23

+ Details

Name:	ifrs-full_GrossFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The maximum exposure to the credit risk of loans or receivables. [Refer: Loans and receivables; Credit risk [member]; Maximum exposure to credit risk]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expired 2023-01-01
-Name IFRS
-Number 7
-IssueDate 2023-01-01
-Paragraph 9
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_9_a&doctype=Standard&book=b
-URIDate 2023-03-23

+ Details

Name:	ifrs-full_MaximumExposureToCreditRiskOfLoansOrReceivables
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of non-financial assets that the entity does not separately disclose in the same statement or note. [Refer: Financial assets]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2023-01-01
-Paragraph 55
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2023-en-r&anchor=para_55&doctype=Standard
-URIDate 2023-03-23

+ Details

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

- Definition

The amount of instruments sold with the intent to reacquire in repurchase agreements and cash collateral on securities lent.

+ References

+ Details

Name:	ifrs-full_RepurchaseAgreementsAndCashCollateralOnSecuritiesLent
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The value of significant unobservable input used in the measurement of the fair value of assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 13
-IssueDate 2023-01-01
-Paragraph 93
-Subparagraph d
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2023-en-r&anchor=para_93_d&doctype=Standard
-URIDate 2023-03-23

+ Details

Name:	ifrs-full_SignificantUnobservableInputAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Assets Sold Under Agreements To Repurchase, Interest Rate1

+ References

No definition available.

+ Details

Name:	slf_AssetsSoldUnderAgreementsToRepurchaseInterestRate1
Namespace Prefix:	slf_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Assets Sold Under Agreements To Repurchase, Maturity Period

+ References

No definition available.

+ Details

Name:	slf_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriod
Namespace Prefix:	slf_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Collateralized Loan Obligation, Asset

+ References

No definition available.

+ Details

Name:	slf_CollateralizedLoanObligationAsset
Namespace Prefix:	slf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Collateralized Loan Obligation, Liability

+ References

No definition available.

+ Details

Name:	slf_CollateralizedLoanObligationLiability
Namespace Prefix:	slf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

[Line Items] For Disclosure Of Fair Value Measurement Of Assets And Liabilities [Table]

+ References

No definition available.

+ Details

Name:	slf_DisclosureOfFairValueMeasurementOfAssetsAndLiabilitiesLineItems
Namespace Prefix:	slf_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Discount Rate, Significant Unobservable Inputs, Assets

+ References

No definition available.

+ Details

Name:	slf_DiscountRateSignificantUnobservableInputsAssets
Namespace Prefix:	slf_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Financial Forecast Of Cash Flows For Cash-Generating Unit, Significant Unobservable Inputs, Assets, Per Square Foot

+ References

No definition available.

+ Details

Name:	slf_FinancialForecastOfCashFlowsForCashGeneratingUnitSignificantUnobservableInputsAssetsPerSquareFoot
Namespace Prefix:	slf_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

Growth Rate, Significant Unobservable Inputs, Assets

+ References

No definition available.

+ Details

Name:	slf_GrowthRateSignificantUnobservableInputsAssets
Namespace Prefix:	slf_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Long-Term Vacancy Rate, Significant Unobservable Inputs, Assets

+ References

No definition available.

+ Details

Name:	slf_LongTermVacancyRateSignificantUnobservableInputsAssets
Namespace Prefix:	slf_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Property, Plant and Equipment Expected Return Period, Significant Unobservable Inputs, Assets

+ References

No definition available.

+ Details

Name:	slf_PropertyPlantandEquipmentExpectedReturnPeriodSignificantUnobservableInputsAssets
Namespace Prefix:	slf_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Realized And Unrealized Losses On Collateralized Loan Obligations

+ References

No definition available.

+ Details

Name:	slf_RealizedAndUnrealizedLossesOnCollateralizedLoanObligations
Namespace Prefix:	slf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Terminal Capitalization Rate, Significant Unobservable Inputs, Assets

+ References

No definition available.

+ Details

Name:	slf_TerminalCapitalizationRateSignificantUnobservableInputsAssets
Namespace Prefix:	slf_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	ifrs-full_TypesOfFinancialLiabilitiesAxis=slf_CashCollateralOnSecuritiesLentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfFinancialAssetsAxis=slf_SecuritizedMortgagesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfFinancialAssetsAxis=slf_AssetBackedSecuritiesInPrincipalReinvestmentAccountMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfFinancialAssetsAxis=slf_CashAndCashEquivalentsInPrincipalReinvestmentAccountMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfFinancialAssetsAxis=slf_AssetRepurchaseAgreementTransferredAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfFinancialAssetsAxis=ifrs-full_SecuritiesLendingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfFinancialAssetsAxis=slf_SecuritiesLendingCollateralMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfAssetsAxis=ifrs-full_InvestmentsAccountedForUsingEquityMethodMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ValuationTechniquesUsedInFairValueMeasurementAxis=ifrs-full_DiscountedCashFlowMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfAssetsAxis=slf_InvestmentPropertiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_RangeAxis=ifrs-full_BottomOfRangeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_UnobservableInputsAxis=ifrs-full_CreditSpreadMeasurementInputMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_UnobservableInputsAxis=slf_LiquidityAdjustmentsPremiumDiscountMeasurementInputMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_TypesOfInvestmentPropertyAxis=slf_RetailAndOfficePropertiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_TypesOfInvestmentPropertyAxis=slf_IndustrialPropertiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_RangeAxis=ifrs-full_TopOfRangeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_RangeAxis=ifrs-full_WeightedAverageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_MeasurementAxis=ifrs-full_AtCostMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_MeasurementAxis=ifrs-full_AtFairValueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfFinancialLiabilitiesAxis=slf_CollateralizedLoanObligationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfFinancialLiabilitiesAxis=slf_SecuritizedMortgagesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_CategoriesOfFinancialAssetsAxis=slf_CashAndAccountsReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_CategoriesOfFinancialAssetsAxis=slf_Loans1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Total Invested Assets and Related Net Investment Income - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 CAD ($) dollarsPerSquareFoot	Dec. 31, 2022 CAD ($)	Dec. 31, 2021 CAD ($)
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Assets supporting CLOs	$ 3,478	$ 2,880
Collateralized loan obligation	3,247	2,816
Realized and unrealized losses on CLOs	43
Other non-financial invested assets (Note 5)	1,657	1,652	$ 1,660
Notional amount	162,948	157,035	$ 174,499
Fair value	162,854	156,900
Financial liabilities	18,902	17,964
Financial liabilities, at fair value	$ 18,801	$ 17,692
Repurchase agreement interest rate	4.86%	3.90%
Carrying value of securities lent	$ 2,705	$ 2,725
Cash collateral on securities lent
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Cash collateral	187	215
Securitized Mortgages
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Notional amount	1,792	1,926
Fair value	1,697	1,793
Securities in Principal Reinvestment Account
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Notional amount	335	244
Cash and cash equivalents in Principal Reinvestment Account
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Notional amount	57	0
Transferred assets
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Fair value	2,705	2,725
Securities lending
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Carrying value of securities lent	2,044	2,202
Collateral associated with securities lending
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Carrying value of securities lent	2,158	2,322
Investments accounted for using equity method
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Other non-financial invested assets (Note 5)	$ 1,657	1,652
Discounted cash flow \| Investment property
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Expected return period	10 years
Bottom of range
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Repurchase agreement maturity period	8 days
Bottom of range \| Discounted cash flow
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Rental growth rate (per annum)	0.00%
Long-term vacancy rate	2.00%
Discount rate	5.50%
Terminal capitalization rate	4.00%
Bottom of range \| Discounted cash flow \| Credit spread, measurement input
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Significant unobservable inputs	0.0050
Bottom of range \| Discounted cash flow \| Liquidity adjustments, premium (discount), measurement input
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Significant unobservable inputs	(0.0100)
Bottom of range \| Retail and office properties \| Discounted cash flow
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Estimated rental value (per square foot, per annum) \| dollarsPerSquareFoot	12.00
Bottom of range \| Industrial properties \| Discounted cash flow
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Estimated rental value (per square foot, per annum) \| dollarsPerSquareFoot	3.00
Top of range
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Repurchase agreement maturity period	365 days
Top of range \| Discounted cash flow
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Rental growth rate (per annum)	3.00%
Long-term vacancy rate	10.00%
Discount rate	10.00%
Terminal capitalization rate	8.50%
Top of range \| Discounted cash flow \| Credit spread, measurement input
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Significant unobservable inputs	0.0450
Top of range \| Discounted cash flow \| Liquidity adjustments, premium (discount), measurement input
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Significant unobservable inputs	0.0200
Top of range \| Retail and office properties \| Discounted cash flow
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Estimated rental value (per square foot, per annum) \| dollarsPerSquareFoot	76.00
Top of range \| Industrial properties \| Discounted cash flow
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Estimated rental value (per square foot, per annum) \| dollarsPerSquareFoot	23.00
Weighted average
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Repurchase agreement maturity period	100 days
At cost
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Other non-financial invested assets (Note 5)	$ 9,723	10,102
At fair value
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Other non-financial invested assets (Note 5)	9,723	10,102
Other financial invested assets (CLOs)
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Maximum contractual exposure to credit risk of loans or receivables	192	159
Financial liabilities	3,247	2,816
Financial liabilities, at fair value	3,247	2,688
Securitized Mortgages
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Financial liabilities	2,119	2,158
Financial liabilities, at fair value	2,021	2,018
Cash and Accounts Receivable
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Assets supporting CLOs	251	292
Loans
Disclosure Of Fair Value Measurement of Assets and Liabilities [Line Items]
Assets supporting CLOs	$ 3,227	$ 2,588