SEGMENT INFORMATION, Classified by Major Geographic Areas (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Sep. 30, 2021
Revenues:
Total net revenues	$ 2,781	$ 2,222
Pre-tax income
Total pre-tax income	558	399
Total assets:
Total assets	68,461		$ 61,891
Goodwill:
Goodwill	660		660
U.S.
Revenues:
Total net revenues	2,589	2,079
Pre-tax income
Total pre-tax income	531	396
Total assets:
Total assets	64,589		57,952
Goodwill:
Goodwill	619		619
Canada
Revenues:
Total net revenues	137	105
Pre-tax income
Total pre-tax income	17	1
Total assets:
Total assets	3,670		3,724
Goodwill:
Goodwill	25		25
Europe
Revenues:
Total net revenues	55	38
Pre-tax income
Total pre-tax income	10	$ 2
Total assets:
Total assets	202		215
Goodwill:
Goodwill	$ 16		$ 16