SEGMENT INFORMATION, Classified by Major Geographic Areas (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Net revenues:
Total revenues	$ 11,003	$ 9,760	$ 7,990
Pre-tax income/(loss):
Total pre-tax income	2,022	1,791	1,052
Total assets:
Aggregate assets	80,951	61,891
Goodwill and Intangible Assets:
Goodwill	1,422	660	466
U.S.
Net revenues:
Total revenues	10,065	9,067	7,446
Pre-tax income/(loss):
Total pre-tax income	1,907	1,701	1,028
Total assets:
Aggregate assets	74,428	57,952
Goodwill and Intangible Assets:
Goodwill	1,250	619
Canada
Net revenues:
Total revenues	542	485	386
Pre-tax income/(loss):
Total pre-tax income	83	53	29
Total assets:
Aggregate assets	3,631	3,724
Goodwill and Intangible Assets:
Goodwill	23	25
Europe
Net revenues:
Total revenues	396	208	158
Pre-tax income/(loss):
Total pre-tax income	32	37	$ (5)
Total assets:
Aggregate assets	2,892	215
Goodwill and Intangible Assets:
Goodwill	$ 149	$ 16