EARNINGS PER SHARE (Details) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended			6 Months Ended
	Sep. 21, 2021	Mar. 31, 2022 USD ($) $ / shares shares	Sep. 30, 2021	Mar. 31, 2021 USD ($) $ / shares shares	Mar. 31, 2022 USD ($) $ / shares shares	Mar. 31, 2021 USD ($) $ / shares shares
Earnings Per Share [Abstract]
Stock split ratio	1.5		1.5
Income for basic earnings per common share:
Net income		$ 323		$ 355	$ 769	$ 667
Less allocation of earnings and dividends to participating securities		0		0	(1)	(1)
Net income attributable to RJF common shareholders		323		355	768	666
Income for diluted earnings per common share:
Net income		323		355	769	667
Less allocation of earnings and dividends to participating securities		0		0	(1)	(1)
Net income attributable to RJF common shareholders		$ 323		$ 355	$ 768	$ 666
Common shares:
Average common shares in basic computation (in shares) | shares		207.7		206.7	207.0	206.0
Dilutive effect of outstanding stock options and certain restricted stock units (in shares) | shares		5.3		5.1	5.6	4.6
Average common and common equivalent shares used in diluted computation (in shares) | shares		213.0		211.8	212.6	210.6
Earnings per common share:
Basic (in dollars per share) | $ / shares		$ 1.56		$ 1.72	$ 3.71	$ 3.23
Diluted (in dollars per share) | $ / shares		$ 1.52		$ 1.68	$ 3.61	$ 3.16
Stock options and certain RSUs excluded from weighted-average diluted common shares because their effect would be antidilutive (in shares) | shares		0.0		0.2	0.5	0.3
Dividends per common share declared and paid: [Abstract]
Dividends per common share - declared (in dollars per share) | $ / shares		$ 0.34		$ 0.26	$ 0.68	$ 0.52
Dividends per common share - paid (in dollars per share) | $ / shares		$ 0.34		$ 0.26	$ 0.60	$ 0.51