Investments (Tables)

3 Months Ended

Mar. 31, 2016

Schedule of Available-for-sale Securities [Line Items]

Marketable Securities

$ in millions	March 31, 2016	December 31, 2015
Available-for-sale investments:
Seed money	174.9	225.9
CLOs	11.8	1.4
Other debt securities	4.3	5.9
Trading investments:
Investments related to deferred compensation plans	166.0	158.8
Seed money	152.8	191.2
Other equity securities	26.3	48.1
UIT-related equity and debt securities	2.2	4.6
Equity method investments	346.8	352.8
Foreign time deposits	28.8	24.7
Other	5.7	5.7
Total investments	919.6	1,019.1

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, 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	—

	For the three months ended March 31, 2015
$ in millions	Proceeds from Sales	Gross Realized Gains	Gross Realized Losses
Seed money	8.9	0.6	—
CLOs	0.9	0.1	—
	9.8	0.7	—

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, 2016					December 31, 2015
$ 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	173.3	8.3	(6.7	)	174.9	227.6	7.6	(9.3	)	225.9
CLOs	11.7	5.1	(5.0	)	11.8	1.3	0.1	—		1.4
Other debt securities	4.1	0.2	—		4.3	5.9	—	—		5.9
	189.1	13.6	(11.7	)	191.0	234.8	7.7	(9.3	)	233.2

Breakdown Of Available-For-Sale Investments with Unrealized Losses

At March 31, 2016, 215 seed money funds (December 31, 2015: 192 seed money funds) had incurred gross unrealized holding losses. The following table provides a breakdown of the unrealized losses.

	March 31, 2016			December 31, 2015
$ in millions	Fair Value	Gross Unrealized Losses		Fair Value	Gross Unrealized Losses
Less than 12 months	4.4	(0.4	)	93.0	(3.0	)
12 months or greater	76.6	(6.3	)	65.5	(6.3	)
Total	81.0	(6.7	)	158.5	(9.3	)

Held-to-maturity Securities [Table Text Block]

Available-for-sale debt securities as of March 31, 2016 by maturity, are set out below:

	Available-for-Sale (Fair Value)
Less than one year	1.7
One to five years	1.5
Five to ten years	10.2
Greater than ten years	2.7
Total available-for-sale	16.1