Comparative Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ 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
Comparative Quarterly Financial Information [Abstract]
Total revenue	$ 451,081	$ 420,819	$ 405,911	$ 452,554	$ 433,740	$ 431,235	$ 411,861	$ 406,416	$ 1,730,365	$ 1,683,252	$ 1,692,422
Operating income	(13,656)	131,221	121,956	134,719	135,433	137,135	127,173	121,130	374,240	520,871	555,202
Net income	(33,946)	26,389	28,056	112,835	118,950	108,536	113,130	92,260	133,334	432,876	397,905
Net income (loss) 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
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