Earnings Per Common Share - Calculation Of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Net income attributable to Invesco Ltd.	$ 267.8	$ 81.5
Weighted average shares outstanding - basic (in shares)	461.6	455.7
Dilutive effect of non-participating common share-based awards (in shares)	3.1	3.2
Weighted average shares outstanding - diluted (in shares)	464.7	458.9
Earnings per common share:
- basic (usd per share)	$ 0.58	$ 0.18
- diluted (usd per share)	$ 0.58	$ 0.18