Earnings Per Common Share - Calculation Of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Net income attributable to Invesco Ltd.	$ 40.5	$ 40.1	$ 122.0	$ 217.8
Weighted average shares outstanding - basic (in shares)	460.1	431.6	457.9	416.7
Dilutive effect of non-participating common share-based awards (in shares)	3.0	2.2	3.1	1.5
Weighted average shares outstanding - diluted (in shares)	463.1	433.8	461.0	418.2
Earnings per common share:
- basic (usd per share)	$ 0.09	$ 0.09	$ 0.27	$ 0.52
- diluted (usd per share)	$ 0.09	$ 0.09	$ 0.26	$ 0.52