AVAILABLE FOR SALE SECURITIES, Contractual Maturities (Details) - USD ($) $ in Millions	Sep. 30, 2020	Sep. 30, 2019
Carrying value [Abstract]
Total	$ 7,650	$ 3,093
RJ Bank
Amortized cost [Abstract]
Within one year	32
After one but within five years	204
After five but within ten years	2,069
After ten years	5,226
Cost basis	7,531	3,065
Carrying value [Abstract]
Within one year	33
After one but within five years	210
After five but within ten years	2,117
After ten years	5,290
Total	$ 7,650	3,093
Weighted-average yield [Abstract]
Within one year (in hundredths)	2.72%
After one but within five years (in hundredths)	2.06%
After five but within ten years (in hundredths)	1.67%
After ten years (in hundredths)	1.41%
Total (in hundredths)	1.51%
RJ Bank | Agency residential MBS
Amortized cost [Abstract]
Within one year	$ 0
After one but within five years	34
After five but within ten years	1,403
After ten years	2,627
Cost basis	4,064	1,555
Carrying value [Abstract]
Within one year	0
After one but within five years	36
After five but within ten years	1,434
After ten years	2,665
Total	4,135	1,574
RJ Bank | Agency commercial MBS
Amortized cost [Abstract]
Within one year	32
After one but within five years	153
After five but within ten years	583
After ten years	180
Cost basis	948	305
Carrying value [Abstract]
Within one year	33
After one but within five years	157
After five but within ten years	598
After ten years	181
Total	969	310
RJ Bank | Agency CMOs
Amortized cost [Abstract]
Within one year	0
After one but within five years	11
After five but within ten years	74
After ten years	2,419
Cost basis	2,504	1,195
Carrying value [Abstract]
Within one year	0
After one but within five years	11
After five but within ten years	75
After ten years	2,444
Total	2,530	1,199
RJ Bank | Other securities
Amortized cost [Abstract]
Within one year	0
After one but within five years	6
After five but within ten years	9
After ten years	0
Cost basis	15	10
Carrying value [Abstract]
Within one year	0
After one but within five years	6
After five but within ten years	10
After ten years	0
Total	$ 16	$ 10