SENIOR NOTES PAYABLE, Schedule of Senior Notes Payable (Details) - USD ($)	1 Months Ended	12 Months Ended
	Apr. 30, 2021	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021	Mar. 31, 2020	May 31, 2017	Jul. 31, 2016	Mar. 31, 2012
Debt Instrument [Line Items]
Purchase/redemption price		$ 0	$ 0	$ 844,000,000
Losses on extinguishment of debt		0	0	98,000,000
Senior notes payable
Debt Instrument [Line Items]
Long-term debt, gross		2,050,000,000	2,050,000,000
Unaccreted premiums/(discounts)		5,000,000	5,000,000
Unamortized debt issuance costs		(16,000,000)	(17,000,000)
Total senior notes payable		2,039,000,000	2,038,000,000
Losses on extinguishment of debt				$ 98,000,000
Senior notes payable | 4.65% senior notes, due 2030
Debt Instrument [Line Items]
Long-term debt, gross		500,000,000	500,000,000
Aggregate principal amount of the notes					$ 500,000,000
Interest rate					4.65%
Percentage of principal amount of notes redeemed					100.00%
Basis spread used in determining redemption price					0.50%
Senior notes payable | 4.95% senior notes, due 2046
Debt Instrument [Line Items]
Long-term debt, gross		800,000,000	800,000,000
Aggregate principal amount of the notes							$ 300,000,000
Interest rate							4.95%
Percentage of principal amount of notes redeemed						100.00%
Basis spread used in determining redemption price						0.45%
Senior notes payable | 4.95% senior notes, due 2046
Debt Instrument [Line Items]
Aggregate principal amount of the notes						$ 500,000,000
Senior notes payable | 3.75% senior notes, due 2051
Debt Instrument [Line Items]
Long-term debt, gross		$ 750,000,000	$ 750,000,000
Aggregate principal amount of the notes	$ 750,000,000
Interest rate	3.75%
Percentage of principal amount of notes redeemed	100.00%
Basis spread used in determining redemption price	0.20%
Senior notes payable | Senior Notes Due 2024
Debt Instrument [Line Items]
Interest rate								5.625%
Purchase/redemption price	$ 250,000,000
Senior notes payable | Senior Notes Due 2026
Debt Instrument [Line Items]
Interest rate							3.625%
Purchase/redemption price	$ 500,000,000