Earnings Per Common Share (Calculation Of Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Net income attributable to Invesco Ltd.	$ 524.8	$ 564.7	$ 882.8
Weighted average shares outstanding - basic (in shares)	459.5	437.8	412.4
Dilutive effect on share-based awards (in shares)	3.0	2.7	0.1
Weighted average shares outstanding - diluted (in shares)	462.5	440.5	412.5
Earnings per common share:
Basic (usd per share)	$ 1.14	$ 1.29	$ 2.14
Diluted (usd per share)	$ 1.13	$ 1.28	$ 2.14