Earnings Per Common Share (Calculation Of Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Net income attributable to Invesco Ltd.	$ 167.1	$ 269.6	$ 384.9	$ 768.6
Weighted average shares outstanding - basic (in shares)	462.8	414.3	432.3	413.2
Dilutive effect of non-participating common share-based awards (in shares)	4.1	0.1	2.3	0.2
Weighted average shares outstanding - diluted (in shares)	466.9	414.4	434.6	413.4
Earnings per common share:
Basic earnings per common share (usd per share)	$ 0.36	$ 0.65	$ 0.89	$ 1.86
Diluted earnings per common share (usd per share)	$ 0.36	$ 0.65	$ 0.89	$ 1.86