AVAILABLE-FOR-SALE SECURITIES, Contractual Maturities (Details) - USD ($) $ in Millions	Mar. 31, 2020	Sep. 30, 2019
Carrying value
Total	$ 4,265	$ 3,093
RJ Bank
Amortized cost
Within one year	0
After one but within five years	226
After five but within ten years	1,147
After ten years	2,781
Cost basis	4,154	3,065
Carrying value
Within one year	0
After one but within five years	232
After five but within ten years	1,187
After ten years	2,846
Total	$ 4,265	3,093
Weighted-average yield
Within one year (in hundredths)	0.00%
After one but within five years (in hundredths)	2.28%
After five but within ten years (in hundredths)	2.34%
After ten years (in hundredths)	2.25%
Total (in hundredths)	2.27%
RJ Bank | Agency residential MBS
Amortized cost
Within one year	$ 0
After one but within five years	32
After five but within ten years	791
After ten years	1,106
Cost basis	1,929	1,555
Carrying value
Within one year	0
After one but within five years	33
After five but within ten years	818
After ten years	1,134
Total	1,985	1,574
RJ Bank | Agency commercial MBS
Amortized cost
Within one year	0
After one but within five years	189
After five but within ten years	265
After ten years	79
Cost basis	533	305
Carrying value
Within one year	0
After one but within five years	193
After five but within ten years	276
After ten years	80
Total	549	310
RJ Bank | Agency CMOs
Amortized cost
Within one year	0
After one but within five years	2
After five but within ten years	79
After ten years	1,596
Cost basis	1,677	1,195
Carrying value
Within one year	0
After one but within five years	2
After five but within ten years	81
After ten years	1,632
Total	1,715	1,199
RJ Bank | Other securities
Amortized cost
Within one year	0
After one but within five years	3
After five but within ten years	12
After ten years	0
Cost basis	15	10
Carrying value
Within one year	0
After one but within five years	4
After five but within ten years	12
After ten years	0
Total	$ 16	$ 10