- Definition

Decrease in distribution expenses relating to fee waivers in certain money market funds to maintain positive or zero net yields.

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- Definition

Decrease in net income attributable to noncontrolling interests relating to fee waivers in certain money market funds to maintain positive or zero net yields.

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- Definition

Decrease in pre-tax income relating to fee waivers in certain money market funds to maintain positive or zero net yields.

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- Definition

Estimated net impact of fee waivers in certain money market funds to maintain positive or zero net yields on future pre-tax income.

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- Definition

Increase In Basis Points In Gross Yields On Securities Purchased In Money Market Fund Portfolios

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- Definition

Percentage decrease on pre-tax income impact of waivers as a result of an increase in basis points in gross yields on securities purchased in money market fund portfolios

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- Definition

Percentage of revenue concentration on total revenue

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- Definition

Voluntary fee waivers in certain money market funds to maintain positive or zero net yields.

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Concentration Risk (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended					9 Months Ended		3 Months Ended				9 Months Ended	3 Months Ended	9 Months Ended		3 Months Ended	9 Months Ended
	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2011 Forecast 1 [Member] basispoints	Dec. 31, 2011 Forecast 2 [Member] basispoints	Dec. 31, 2011 Minimum [Member]	Sep. 30, 2011 Federated Kaufmann Fund [Member] Revenue Concentration By Product [Member]	Sep. 30, 2011 Federated Kaufmann Fund [Member] Revenue Concentration By Product [Member]	Sep. 30, 2011 Federated Prime Obligations Fund [Member] Revenue Concentration By Product [Member]	Sep. 30, 2011 Federated Prime Obligations Fund [Member] Revenue Concentration By Product [Member]	Sep. 30, 2011 Revenue Concentration by Asset Class [Member]	Sep. 30, 2011 Revenue Concentration By Customer [Member]	Sep. 30, 2011 Revenue Concentration By Customer [Member]
Percentage Decrease Pre-tax Income Impact Of Waivers								40.00%	70.00%
Percentage of revenue concentration on total revenue											12.00%	12.00%	11.00%	11.00%	46.00%	9.00%	10.00%
Waiver of fees						$ 231.7	$ 181.6
Reduction in distribution expenses						170.5	138.9
Reduction in pre-tax income	23.2	19.4	13.1	12.1	11.0	55.7	41.8
Estimated net impact of fee waivers on future pre-tax income										26
Increase In Basis Points In Gross Yields On Securities Purchased In Money Market Fund Portfolios								10	25
Reduction in net income attributable to noncontrolling interests						$ 5.5	$ 0.9