Consolidation - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accounts receivable from Federated Funds	$ 42,000,000		$ 42,000,000		$ 27,400,000
Fee waivers	89,300,000	$ 83,800,000	264,900,000	$ 259,200,000
Non-Consolidated Variable Interest Entity, Not Primary Beneficiary | Receivables from Federated Funds
Variable Interest Entities [Line Items]
Federated's maximum risk of loss in non-consolidated investment companies	19,200,000		19,200,000		2,300,000
Non-Consolidated Variable Interest Entity, Not Primary Beneficiary | Investments—Affiliates and Other
Variable Interest Entities [Line Items]
Federated's maximum risk of loss in non-consolidated investment companies					900,000
AUM for nonconsolidated Federated Funds					$ 55,800,000
Financial Support, Fee Waivers
Variable Interest Entities [Line Items]
Money market funds which meet the scope exception of the consolidation guidance	61,300,000	53,100,000	178,900,000	166,700,000
Financial Support, Capital Contributions
Variable Interest Entities [Line Items]
Money market funds which meet the scope exception of the consolidation guidance	$ 0	$ 0	$ 0	$ 0