Share-based payments - ESP Option Activity (Details) - ESP	6 Months Ended
Jun. 30, 2018 CAD ($) shares
Disclosure of terms and conditions of share-based payment arrangement [line items]
Unvested contributions, January 1, 2018 (in shares)	1,039,030
Granted (in shares)	331,987
Dividends credited (in shares)	26,960
Vested (in shares)	(255,867)
Forfeited (in shares)	(71,395)
Unvested contributions, June 30, 2018 (in shares)	1,070,715
Weighted average fair value at measurement date, other equity instruments granted \| $	$ 56

Number Of Other Equity Instruments Dividends Credited Share-Based Payment Arrangement

No definition available.

Name:	bce_NumberOfOtherEquityInstrumentsDividendsCreditedShareBasedPaymentArrangement
Namespace Prefix:	bce_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

The number of other equity instruments (ie other than share options) granted in a share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2017-01-01
-Paragraph 47
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=2&date=2017-03-01&anchor=para_47_b&doctype=Standard
-URIDate 2017-03-09

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IFRS
-Number 2
-IssueDate 2017-01-01
-Paragraph 45
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=2&date=2017-03-01&anchor=para_45&doctype=Standard
-URIDate 2017-03-09

+ Details

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

- Definition

The number of other equity instruments (ie other than share options) exercisable in a share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IFRS
-Number 2
-IssueDate 2017-01-01
-Paragraph 45
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=2&date=2017-03-01&anchor=para_45&doctype=Standard
-URIDate 2017-03-09

+ Details

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

- Definition

The number of other equity instruments (ie other than share options) exercised or vested in a share-based payment arrangement.

+ References

+ Details

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

- Definition

The number of other equity instruments (ie other than share options) forfeited in a share-based payment arrangement.

+ References

+ Details

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

- Definition

The weighted average fair value at the measurement date of granted equity instruments other than share options. [Refer: Weighted average [member]]

+ References

+ Details

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

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=bce_EmployeeSharePurchasePlanESPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: