SHAREHOLDERS' EQUITY, Schedule of Accumulated Other Comprehensive (Loss) Income (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of year	$ 9,432	$ 8,303
OCI:
OCI before reclassifications and taxes	42	(1,214)	$ (96)
Amounts reclassified from AOCI, before tax	(32)	9	10
Pre-tax net OCI	10	(1,205)	(86)
Income tax effect	1	264	34
Total other comprehensive income/(loss), net of tax	11	(941)	(52)
Balance, end of year	10,187	9,432	8,303
Accumulated other comprehensive (loss) income
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of year	(982)	(41)	11
OCI:
Balance, end of year	(971)	(982)	(41)
Subtotal: net investment hedges and currency translations
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of year	(123)	(9)	(25)
OCI:
OCI before reclassifications and taxes	46	(91)	4
Amounts reclassified from AOCI, before tax	0	0	2
Pre-tax net OCI	46	(91)	6
Income tax effect	4	(23)	10
Total other comprehensive income/(loss), net of tax	50	(114)	16
Balance, end of year	(73)	(123)	(9)
Net investment hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of year	153	81	115
OCI:
OCI before reclassifications and taxes	(14)	95	(44)
Amounts reclassified from AOCI, before tax	0	0	0
Pre-tax net OCI	(14)	95	(44)
Income tax effect	4	(23)	10
Total other comprehensive income/(loss), net of tax	(10)	72	(34)
Balance, end of year	143	153	81
Currency translations
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of year	(276)	(90)	(140)
OCI:
OCI before reclassifications and taxes	60	(186)	48
Amounts reclassified from AOCI, before tax	0	0	2
Pre-tax net OCI	60	(186)	50
Income tax effect	0	0	0
Total other comprehensive income/(loss), net of tax	60	(186)	50
Balance, end of year	(216)	(276)	(90)
Available-for-sale securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of year	(902)	(5)	89
OCI:
OCI before reclassifications and taxes	(37)	(1,208)	(119)
Amounts reclassified from AOCI, before tax	0	0	(7)
Pre-tax net OCI	(37)	(1,208)	(126)
Income tax effect	(3)	311	32
Total other comprehensive income/(loss), net of tax	(40)	(897)	(94)
Balance, end of year	(942)	(902)	(5)
Cash flow hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of year	43	(27)	(53)
OCI:
OCI before reclassifications and taxes	33	85	19
Amounts reclassified from AOCI, before tax	(32)	9	15
Pre-tax net OCI	1	94	34
Income tax effect	0	(24)	(8)
Total other comprehensive income/(loss), net of tax	1	70	26
Balance, end of year	$ 44	$ 43	$ (27)