SHAREHOLDERS' EQUITY, Changes in Components of AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of year	$ 11,667	$ 10,187
OCI:
Balance, end of year	12,504	11,667	$ 10,187
Accumulated other comprehensive (loss) income
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of year	(502)	(971)	(982)
OCI:
OCI before reclassifications and taxes	159	641	42
Amounts reclassified from AOCI, before tax	(12)	(35)	(32)
Pre-tax net OCI	147	606	10
Income tax effect	(41)	(137)	1
Total other comprehensive income, net of tax	106	469	11
Balance, end of year	(396)	(502)	(971)
Subtotal: net investment hedges and currency translations
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of year	(24)	(73)	(123)
OCI:
OCI before reclassifications and taxes	25	49	46
Amounts reclassified from AOCI, before tax	0	0	0
Pre-tax net OCI	25	49	46
Income tax effect	(13)	0	4
Total other comprehensive income, net of tax	12	49	50
Balance, end of year	(12)	(24)	(73)
Net investment hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of year	145	143	153
OCI:
OCI before reclassifications and taxes	52	2	(14)
Amounts reclassified from AOCI, before tax	0	0	0
Pre-tax net OCI	52	2	(14)
Income tax effect	(13)	0	4
Total other comprehensive income, net of tax	39	2	(10)
Balance, end of year	184	145	143
Currency translations
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of year	(169)	(216)	(276)
OCI:
OCI before reclassifications and taxes	(27)	47	60
Amounts reclassified from AOCI, before tax	0	0	0
Pre-tax net OCI	(27)	47	60
Income tax effect	0	0	0
Total other comprehensive income, net of tax	(27)	47	60
Balance, end of year	(196)	(169)	(216)
Available-for-sale securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of year	(485)	(942)	(902)
OCI:
OCI before reclassifications and taxes	122	606	(37)
Amounts reclassified from AOCI, before tax	2	0	0
Pre-tax net OCI	124	606	(37)
Income tax effect	(30)	(149)	(3)
Total other comprehensive income, net of tax	94	457	(40)
Balance, end of year	(391)	(485)	(942)
Cash flow hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, beginning of year	7	44	43
OCI:
OCI before reclassifications and taxes	12	(14)	33
Amounts reclassified from AOCI, before tax	(14)	(35)	(32)
Pre-tax net OCI	(2)	(49)	1
Income tax effect	2	12	0
Total other comprehensive income, net of tax	0	(37)	1
Balance, end of year	$ 7	$ 7	$ 44