Earnings Per Share (Summary schedule of the calculation of earnings per basic and diluted shares) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Oct. 31, 2020	Jul. 31, 2020	Apr. 30, 2020	Jan. 31, 2020	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2018
Earnings Per Share Reconciliation [Abstract]
Net income attributable to Eaton Vance Corp. shareholders	$ (35,934)	$ (1,593)	$ 72,058	$ 103,985	$ 109,206	$ 102,221	$ 101,807	$ 86,801	$ 138,516	$ 400,035	$ 381,938
Weighted-average shares outstanding - basic									109,617	110,064	114,745
Incremental common shares									6,118	4,324	8,187
Weighted-average shares outstanding - diluted									115,735	114,388	122,932
Earnings per share (Basic) ($ per share)	$ (0.32)	$ (0.01)	$ 0.66	$ 0.95	$ 1.00	$ 0.94	$ 0.92	$ 0.77	$ 1.26	$ 3.63	$ 3.33
Earnings per share (Diluted) ($ per share)	$ (0.31)	$ (0.01)	$ 0.65	$ 0.91	$ 0.96	$ 0.90	$ 0.89	$ 0.75	$ 1.20	$ 3.50	$ 3.11