LEGAL PROCEEDINGS - Securities Class Actions and Related Matters (Details) $ in Millions, $ in Millions			9 Months Ended	12 Months Ended	23 Months Ended
	Aug. 04, 2020 CAD ($)	Dec. 07, 2017 insurance_policy_period	Sep. 30, 2023 action group case	Dec. 31, 2015 case	Jun. 30, 2023 USD ($)	May 22, 2023 defendant	Jul. 20, 2021 insured	Mar. 17, 2021 number_business	Feb. 15, 2019 entity
US Securities Litigation, Opt-Out Action | New Jersey
Loss Contingencies [Line Items]
Number of groups of investors filing action | group			37
Number of claims dismissed | case			16
Number of groups of investors filing action, remain pending | group			21
Number of defendants fully dismissed | defendant						0
Canadian Securities Litigation | Canada
Loss Contingencies [Line Items]
Number of suits filed | case				6
Canadian Securities Litigation | Canada | Violation of Canadian Provincial Securities Legislation
Loss Contingencies [Line Items]
Number of suits filed but not yet served | action			2
Number of entities, exercised opt-out right, pursuing action								4	1
Canadian Securities Litigation | Settled Litigation | Canada | Violation of Canadian Provincial Securities Legislation
Loss Contingencies [Line Items]
Settlement, agreed to pay | $	$ 94
Insurance Coverage Lawsuit
Loss Contingencies [Line Items]
Number of distinct insurance policy periods | insurance_policy_period		2
Insurance Coverage Lawsuit | Settled Litigation
Loss Contingencies [Line Items]
Settlement agreements, number of insurers | insured							2
Aggregate amount to be received | $					$ 313