Investments (Tables)

3 Months Ended

Mar. 31, 2017

Investments [Abstract]

Marketable Securities

$ in millions	March 31, 2017	December 31, 2016
Available-for-sale investments:
Seed money	97.8	127.9
CLOs	10.8	12.9
Other debt securities	12.9	13.2
Trading investments:
Investments related to deferred compensation plans	81.8	170.5
Seed money	123.2	121.9
Other equity securities	33.3	30.4
UIT-related equity and debt securities	3.9	6.8
Equity method investments	291.4	279.0
Foreign time deposits	28.5	26.9
Other	5.7	5.8
Total investments	689.3	795.3

Realized Gains Losses Available-For-Sale Securities

Realized gains and losses recognized in the Condensed Consolidated Statements of Income during the period from investments classified as available-for-sale are as follows:

	For the three months ended March 31, 2017
$ in millions	Proceeds from Sales	Gross Realized Gains	Gross Realized Losses
Seed money	34.2	1.6	(1.3	)
CLOs	2.0	0.3	—
Other debt securities	7.6	—	—
	43.8	1.9	(1.3	)

	For the three months ended March 31, 2016
$ in millions	Proceeds from Sales	Gross Realized Gains	Gross Realized Losses
Seed money	1.2	0.3	—
CLOs	0.5	—	—
Other debt securities	1.6	—	—
	3.3	0.3	—

Gross Unrealized Holding Gains And Losses Recognized In Other Accumulated Comprehensive Income From Available-For-Sale Investments

Gross unrealized holding gains and losses recognized in other accumulated comprehensive income from available-for-sale investments are presented in the table below:

	March 31, 2017					December 31, 2016
$ in millions	Cost	Gross Unrealized Holding Gains	Gross Unrealized Holding Losses		Fair Value	Cost	Gross Unrealized Holding Gains	Gross Unrealized Holding Losses		Fair Value
Seed money	93.3	7.0	(2.5	)	97.8	127.2	6.8	(6.1	)	127.9
CLOs	7.5	3.3	—		10.8	9.2	3.7	—		12.9
Other debt securities	12.9	—	—		12.9	13.2	—	—		13.2
	113.7	10.3	(2.5	)	121.5	149.6	10.5	(6.1	)	154.0

Breakdown Of Available-For-Sale Investments with Unrealized Losses

At March 31, 2017, 92 seed money funds (December 31, 2016: 103 seed money funds) had incurred gross unrealized holding losses. The following table provides a breakdown of the unrealized losses.

	March 31, 2017			December 31, 2016
$ in millions	Fair Value	Gross Unrealized Losses		Fair Value	Gross Unrealized Losses
Less than 12 months	0.6	(0.1	)	1.9	(0.2	)
12 months or greater	39.9	(2.4	)	56.4	(5.9	)
Total	40.5	(2.5	)	58.3	(6.1	)

Held-to-maturity Securities [Table Text Block]

Available-for-sale debt securities as of March 31, 2017 by maturity, are set out below:

	Available-for-Sale (Fair Value)
Less than one year	12.9
One to five years	0.2
Five to ten years	7.9
Greater than ten years	2.7
Total available-for-sale	23.7