Related Party Transactions (Sponsored Funds Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017
Sponsored Funds
Management fees waived by the Company	$ 19.1	$ 17.6	$ 16.7
Related party expenses all-in-management fee (excluding investment advisory and administrative fees)	13.2	14.2	15.3
Sponsored Funds [Member]
Sponsored Funds
Subsidies fees waived by the Company	27.7	26.9	$ 13.9
Included in management fees and other accounts receivable	104.1	104.9
Included in accounts payable and accrued expenses	$ 2.2	$ 3.2