FAIR VALUE, Significant Assumptions Used in Valuation of Financial Instruments (Details) - Nonrecurring $ in Millions	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)
Residential mortgage loans
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Bank loans, net	$ 12	$ 14
Residential mortgage loans | Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Bank loans, net	2	3
Residential mortgage loans | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Bank loans, net	$ 10	$ 11
Residential mortgage loans | Level 3 | Minimum | Prepayment rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Bank loans, measurement input	7	7
Residential mortgage loans | Level 3 | Maximum | Prepayment rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Bank loans, measurement input	12	12
Residential mortgage loans | Level 3 | Weighted Average | Prepayment rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Bank loans, measurement input	10.4	10.5
Corporate loans
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Bank loans, net	$ 57	$ 49
Corporate loans | Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Bank loans, net	0	0
Corporate loans | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Bank loans, net	$ 57	$ 49
Corporate loans | Level 3 | Recovery rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Bank loans, measurement input		0.74
Corporate loans | Level 3 | Minimum | Recovery rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Bank loans, measurement input	0.24
Corporate loans | Level 3 | Maximum | Recovery rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Bank loans, measurement input	0.66
Corporate loans | Level 3 | Weighted Average | Recovery rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Bank loans, measurement input	0.47
Loans held for sale
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Bank loans, net	$ 3	$ 29
Loans held for sale | Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Bank loans, net	3	29
Loans held for sale | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Bank loans, net	$ 0	$ 0