Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net Income	$ 168.8	$ 544.8
Other Comprehensive Income (Loss)
Currency translation adjustments, net of tax	127.3	(6.9)
Net unrealized losses on defined benefit plans, net of tax	(2.6)	(5.1)
Other comprehensive income (loss)	124.7	(12.0)
Total comprehensive income	293.5	532.8
Less: comprehensive income (loss) attributable to
Redeemable noncontrolling interests	(1.5)	7.5
Nonredeemable noncontrolling interests	4.7	84.1
Comprehensive Income Attributable to Franklin Resources, Inc.	$ 290.3	$ 441.2