NET LOSS PER SHARE - Anti dilutive securities (Details) - shares shares in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Securities not included in the computation of diluted earnings (loss) per share
Anti dilutive securities	19.1	18.6
Restricted stock units
Securities not included in the computation of diluted earnings (loss) per share
Anti dilutive securities	9.1	9.9
Performance-conditioned stock units
Securities not included in the computation of diluted earnings (loss) per share
Anti dilutive securities	3.5	2.5
Market-conditioned stock units
Securities not included in the computation of diluted earnings (loss) per share
Anti dilutive securities	2.9	2.4
Employee Stock Option
Securities not included in the computation of diluted earnings (loss) per share
Anti dilutive securities	3.6	3.7