Consolidated Investment Products (Beginning And Ending Fair Value Measurements For Level 3 Assets And Liabilities) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Purchase recorded relating to the CLO investment	$ 52.2
Sales recorded relating the CLO investment	187.6
Settlements recorded relating to the CLO investment	530.4
Net unrealized gains/losses attributable to investments	24.1		46.5
VIEs [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	972.8		667.1
Purchases, sales, issuances and settlements/prepayments, net	(135.4)		(81.2)	[1]
Acquisition of business, Assets	0		289.9
Gain and losses included in the Condensed Consolidated Statement of Income, level 3 assets	81.1		97.0	[2]
Foreign exchange, Level 3 Assets	10.6		0
Ending balance	929.1		972.8
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance (Liability)	(5,865.4)		(5,234.9)
Purchases, sales, issuances and settlements/prepayments, net, Level 3 Liabilities	530.4	[1]	209.1	[1]
Acquisition of business, Liabilities	0		(630.2)
Foreign exchange movements included in earnings (Liability)	(74.1)	[2]	(414.3)	[2]
Foreign exchange, Level 3 Liabilities	(103.8)		204.9
Ending Balance (Liability)	$ (5,512.9)		$ (5,865.4)

[1] Prior to the adoption of guidance included in ASU 2010-06, discussed in Note 1, “Accounting Policies,” purchases, sales, issuances and settlements/prepayments were presented net. For the year ended December 31, 2011, the consolidated private equity and real estate funds recorded $52.2 million related to purchase activity and $187.6 million of sale activity, respectively, of level 3 assets. For the year ended December 31, 2011, the consolidated CLOs recorded $530.4 million related to the settlement of level 3 liabilities.

[2] Included in gains and losses of consolidated investment products in the Condensed Consolidated Statement of Income for the year ended December 31, 2011 are $24.1 million in net unrealized gains attributable to investments still held at December 31, 2011 by consolidated investment products (year ended December 31, 2010: $46.5 million net unrealized gains attributable to investments still held at December 31, 2010).