Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 1,161.0	$ 868.3	$ 964.1
Other comprehensive income/(loss), net of tax:
Currency translation differences on investments in foreign subsidiaries	389.4	(314.1)	(493.9)
Actuarial gain/(loss) related to employee benefit plans	21.1	(39.5)	11.1
Prior service credit related to employee benefit plans	0.0	(3.1)	0.0
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), after Tax	5.9	(5.5)	0.0
Reclassification of prior service (credit)/costs into employee compensation expense	0.0	(7.0)	(7.2)
Reclassification of actuarial (gains)/losses into employee compensation expense	2.5	1.5	2.2
Share of other comprehensive income/(loss) of equity method investments	(0.5)	(1.1)	(0.6)
Unrealized gains/(losses) on available-for-sale investments	5.1	5.2	(6.0)
Reclassification of net (gains)/losses realized on available-for-sale investments included in other gains and losses	(5.4)	0.3	(0.4)
Other comprehensive income/(loss)	418.1	(363.3)	(494.8)
Total comprehensive income/(loss)	1,579.1	505.0	469.3
Comprehensive (income)/loss attributable to noncontrolling interests in consolidated entities	(33.7)	(14.1)	4.0
Comprehensive income attributable to Invesco Ltd.	$ 1,545.4	$ 490.9	$ 473.3