ACQUISITION OF BUSINESSES - Business Services (Details) - Business services - Imagine Communications Group Limited And Tuck-in Acquisitions $ in Millions	Dec. 31, 2018 USD ($)
Disclosure of detailed information about business combination [line items]
Consideration transferred, acquisition-date fair value	$ 25
Percentage of voting equity interests acquired	50.00%

The fair value, at acquisition date, of the consideration transferred in a business combination. [Refer: Business combinations [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 3
-IssueDate 2018-01-01
-Paragraph B64
-Subparagraph f
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=3&date=2018-03-01&anchor=para_B64_f&doctype=Appendix&seq=2
-URIDate 2018-03-16

+ Details

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

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

- Definition

The percentage of voting equity interests acquired in a business combination. [Refer: Business combinations [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 3
-IssueDate 2018-01-01
-Paragraph B64
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=3&date=2018-03-01&anchor=para_B64_c&doctype=Appendix&seq=2
-URIDate 2018-03-16

+ Details

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

- Details

Name:	ifrs-full_SegmentsAxis=bbu_BusinessServicesSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_BusinessCombinationsAxis=bbu_ImagineCommunicationsGroupLimitedAndTuckinAcquisitionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: