Redeemable Noncontrolling Interests (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Noncontrolling Interest [Line Items]
Balance at beginning of period	$ 1,525.8
Net income (loss)	(1.5)	$ 7.5
Net subscriptions (distributions) and other	95.9	(27.8)
Net consolidations (deconsolidations)	(35.7)
Balance at End of Period	1,979.2
Minority Interests [Member]
Noncontrolling Interest [Line Items]
Balance at beginning of period	583.6	310.5
Net income (loss)	10.7	12.3
Net subscriptions (distributions) and other	5.2	(1.9)
Net consolidations (deconsolidations)	0.0	0.0
Balance at End of Period	599.5	320.9
Redeemable Noncontrolling Interests [Member]
Noncontrolling Interest [Line Items]
Balance at beginning of period	1,525.8	933.0
Net income (loss)	(1.5)	7.5
Net subscriptions (distributions) and other	183.6	164.4
Net consolidations (deconsolidations)	271.3	(121.5)
Balance at End of Period	1,979.2	983.4
CIPs [Member]
Noncontrolling Interest [Line Items]
Balance at beginning of period	942.2	622.5
Net income (loss)	(12.2)	(4.8)
Net subscriptions (distributions) and other	178.4	166.3
Net consolidations (deconsolidations)	271.3	(121.5)
Balance at End of Period	$ 1,379.7	$ 662.5