The increase (decrease) in equity resulting from the exercise of options.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 106
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_106_d&doctype=Standard
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_IncreaseDecreaseThroughExerciseOfOptions
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The nominal value of capital issued.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 78
-Subparagraph e
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_78_e&doctype=Standard
-URIDate 2019-03-27

+ Details

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

- Definition

The number of share options exercised in a share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2019-01-01
-Paragraph 45
-Subparagraph b
-Clause iv
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2019-en-r&anchor=para_45_b_iv&doctype=Standard
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_NumberOfShareOptionsExercisedInSharebasedPaymentArrangement
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- 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 2019-01-01
-Paragraph 79
-Subparagraph a
-Clause iv
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_79_a_iv&doctype=Standard
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_NumberOfSharesOutstanding
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash outflow to acquire or redeem entity's shares.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 7
-IssueDate 2019-01-01
-Paragraph 17
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2019-en-r&anchor=para_17_b&doctype=Standard
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_PaymentsToAcquireOrRedeemEntitysShares
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The decrease in equity resulting from the purchase of treasury shares. [Refer: Treasury shares]

+ References

+ Details

Name:	ifrs-full_PurchaseOfTreasuryShares
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

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

- Definition

Increase (Decrease) In Number Of Shares Outstanding Through Business Combination

+ References

No definition available.

+ Details

Name:	slf_IncreaseDecreaseInNumberOfSharesOutstandingThroughBusinessCombination
Namespace Prefix:	slf_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Increase (Decrease) In Number Of Shares Outstanding Through Business Combination, Value

+ References

No definition available.

+ Details

Name:	slf_IncreaseDecreaseInNumberOfSharesOutstandingThroughBusinessCombinationValue
Namespace Prefix:	slf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Increase (Decrease) In Number Of Shares Outstanding Through Purchase Of Treasury Shares

+ References

No definition available.

+ Details

Name:	slf_IncreaseDecreaseInNumberOfSharesOutstandingThroughPurchaseOfTreasuryShares
Namespace Prefix:	slf_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Number Of Shares Authorised For Repurchase And Cancellation Of Treasury Shares

+ References

No definition available.

+ Details

Name:	slf_NumberOfSharesAuthorisedForRepurchaseAndCancellationOfTreasuryShares
Namespace Prefix:	slf_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Purchase And Cancellation Of Treasury Shares, Price Per Share

+ References

No definition available.

+ Details

Name:	slf_PurchaseAndCancellationOfTreasurySharesPricePerShare
Namespace Prefix:	slf_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	ifrs-full_ClassesOfShareCapitalAxis=ifrs-full_OrdinarySharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	slf_ShareRepurchaseProgram1Axis=slf_A2018NCIBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	slf_ShareRepurchaseProgram1Axis=slf_ThirdPartyShareRepurchaseProgramMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	slf_ShareRepurchaseProgram1Axis=slf_A2018NCIBAnd2019NCIBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Share Capital - Common Shares Issued and Outstanding (Details)	12 Months Ended
	Dec. 31, 2019 CAD ($) shares $ / shares	Dec. 31, 2018 CAD ($) shares $ / shares	Aug. 14, 2019 shares	Aug. 14, 2018 shares	Aug. 14, 2017 shares
Reconciliation of number of shares outstanding [abstract]
Stock options exercised (in shares)	772,000	399,000
Common shares issued as consideration for business acquisition (in shares)	0	100,000
Common shares issued as consideration for business acquisition \| $	$ 0	$ 4,000,000
Payments to acquire or redeem entity's shares \| $	$ 592,000,000	$ 641,000,000
Common shares
Reconciliation of number of shares outstanding [abstract]
Number of shares outstanding, beginning of year (in shares)	598,500,000	610,500,000
Stock options exercised (in shares)	800,000	400,000
Common shares purchased for cancellation (in shares)	(11,500,000)	(12,500,000)
Number of shares outstanding, end of year (in shares)	587,800,000	598,500,000
Balance, beginning of year \| $	$ 8,419,000,000	$ 8,582,000,000
Stock options exercised \| $	28,000,000	16,000,000
Common shares purchased for cancellation \| $	(158,000,000)	(183,000,000)
Balance, end of year \| $	$ 8,289,000,000	$ 8,419,000,000
Number of shares authorized for purchase and cancellation (in shares)			15,000,000	18,000,000	11,500,000.0
Purchase and cancellation of treasury shares (cad per share) \| $ / shares	$ 52.01	$ 44.91
Payments to acquire or redeem entity's shares \| $	$ 592,000,000	$ 0
2018 NCIB \| Common shares
Reconciliation of number of shares outstanding [abstract]
Common shares purchased for cancellation (in shares)		100,000.0
Third-Party Share Repurchase Program \| Common shares
Reconciliation of number of shares outstanding [abstract]
Common shares purchased for cancellation (in shares)		1,100,000
2018 NCIB and 2019 NCIB \| Common shares
Reconciliation of number of shares outstanding [abstract]
Common shares purchased for cancellation (in shares)	11,400,000.0