Consolidated statements of comprehensive income (Parenthetical) - CAD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Statement of comprehensive income [abstract]
Income tax relating to cash flow hedges	$ (4)	$ (2)	$ 16	$ (5)
Income tax relating to actuarial (losses) gains of defined benefit plans	84	(136)	118	(94)
Income tax relating to changes in fair value of financial liability attributable to change in credit risk of liability included in other comprehensive income	$ 4	$ (6)	$ 8	$ (13)
Actuarial assumption of discount rates	3.00%	3.70%	3.00%	3.70%	3.30%	3.80%	3.60%	3.60%

Income Tax Relating To Other Comprehensive Income, Cash Flow Hedges, Not To Be Reclassified To Net Profit Or Loss

No definition available.

Name:	bce_IncomeTaxRelatingToOtherComprehensiveIncomeCashFlowHedgesNotToBeReclassifiedToNetProfitOrLoss
Namespace Prefix:	bce_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The discount rate used as the significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit obligation, at present value; Actuarial assumptions [member]]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2018-01-01
-Paragraph 144
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_144&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_ActuarialAssumptionOfDiscountRates
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of income tax relating to amounts recognised in other comprehensive income in relation to cash flow hedges. [Refer: Cash flow hedges [member]; Other comprehensive income]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 12
-IssueDate 2018-01-01
-Paragraph 81
-Subparagraph ab
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=12&date=2018-03-01&anchor=para_81_ab&doctype=Standard
-URIDate 2018-03-16

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 90
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_90&doctype=Standard
-URIDate 2018-03-16

+ Details

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

- Definition

The amount of income tax relating to amounts recognised in other comprehensive income in relation to remeasurements of defined benefit plans. [Refer: Other comprehensive income; Reserve of remeasurements of defined benefit plans; Defined benefit plans [member]]

+ References

+ Details

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

- References

No definition available.

+ Details

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