Acquisitions (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
	Jul. 31, 2013	Jul. 31, 2013
Clifton Group [Member]
Business Acquisition Purchase Price Allocation [Line Items]
Business acquisition cost of acquired entity cash paid	$ 72.3	$ 72.3
Business acquisition cost of acquired entity other noncash consideration	12.8	12.8
Business acquisition purchase price allocation amortizable intangible assets	24.5	24.5
Business acquisition purchase price allocation goodwill amount	60.1	60.1
Business acquisition revenues	7.2	15.6
Business acquisition earnings	2.1	4.3
Finite-Lived Intangible Assets, Weighted-Average Useful Life		18 years
Parametric Portfolio Associates [Member]
Business Acquisition Contingent Consideration [Line Items]
Minority interest ownership percentage purchased by parent	3.40%	3.40%
Company's increase in profit interest percentage, during the period	5.70%	5.70%
Non-controlling interest holders profits interest, end of period	4.90%	4.90%
Profits interest granted to non-controlling interest holders	0.76%	0.76%
Company's profit interest percentage, end of period	93.30%	93.30%
Purchase of non-controlling interests		43.5
Company's capital ownership interest at the end of the period	98.10%	98.10%
Noncontrolling capital and profits interest issued in acquisition	1.90%	1.90%
Tax Advantaged Bond Strategies [Member]
Business Acquisition Contingent Consideration [Line Items]
Contingent payment made during the period	14.1	14.1
Goodwill acquired		14.1
Parametric Risk Advisors [Member]
Business Acquisition Contingent Consideration [Line Items]
Minority interest ownership percentage purchased by parent	10.00%	10.00%
Company's capital ownership interest, beginning of period	70.00%	70.00%
Company's capital ownership interest at the end of the period	80.00%	80.00%
Non-controlling interest call option recorded in other liabilities	$ 3.1	$ 3.1
Settlement date		Nov. 01, 2013