DIRECT OPERATING COSTS - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Analysis of income and expense [abstract]
Cumulative benefit	$ 256	$ 256	$ 497	$ 515

Tax Cuts And Jobs Act, Incomplete Accounting, Change In Tax Rate, Provisional Income Tax Expense (Benefit)

No definition available.

Name:	bbu_TaxCutsAndJobsActIncompleteAccountingChangeInTaxRateProvisionalIncomeTaxExpenseBenefit
Namespace Prefix:	bbu_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration