Consolidated Investment Products (Condensed Consolidating Balance Sheet Line Items Reflecting Impact Of Consolidation Of Investment Products Into The Condensed Consolidated Balance Sheets) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010
Current assets	$ 3,834.1		$ 4,274.5
Non-current assets	15,512.9		16,169.6
Total assets	19,347.0		20,444.1
Current liabilities	2,974.4		3,264.5
Long-term debt of consolidated investment products	5,512.9		5,865.4
Other non-current liabilities	1,722.1		1,953.3
Total liabilities	10,209.4		11,083.2
Retained earnings appropriated for investors in consolidated investment products	334.3		495.5
Other equity attributable to common shareholders	7,784.8		7,769.1
Equity attributable to noncontrolling interests in consolidated entities	1,018.5		1,096.3
Total liabilities and equity	19,347.0		20,444.1
Consolidated Investment Products [Member]
Current assets	481.4		794.5
Non-current assets	6,536.4		7,144.5
Total assets	7,017.8		7,939.0
Current liabilities	155.5		486.6
Long-term debt of consolidated investment products	5,512.9		5,865.4
Other non-current liabilities	0		0
Total liabilities	5,668.4		6,352.0
Retained earnings appropriated for investors in consolidated investment products	334.3		495.5
Other equity attributable to common shareholders	1.1		0
Equity attributable to noncontrolling interests in consolidated entities	1,014.0		1,091.5
Total liabilities and equity	7,017.8		7,939.0
CLOs - VIEs [Member]
Current assets	394.5		679.3
Non-current assets	5,682.3		6,204.6
Total assets	6,076.8		6,883.9
Current liabilities	179.2		500.2
Long-term debt of consolidated investment products	5,563.3		5,888.2
Other non-current liabilities	0		0
Total liabilities	5,742.5		6,388.4
Retained earnings appropriated for investors in consolidated investment products	334.3		495.5
Other equity attributable to common shareholders	0		0
Equity attributable to noncontrolling interests in consolidated entities	0		0
Total liabilities and equity	6,076.8		6,883.9
Other VIEs [Member]
Current assets	3.1		3.7
Non-current assets	42.8		59.6
Total assets	45.9		63.3
Current liabilities	0.4		0.9
Long-term debt of consolidated investment products	0		0
Other non-current liabilities	0		0
Total liabilities	0.4		0.9
Retained earnings appropriated for investors in consolidated investment products	0		0
Other equity attributable to common shareholders	0.1		0.1
Equity attributable to noncontrolling interests in consolidated entities	45.4		62.3
Total liabilities and equity	45.9		63.3
VOEs [Member]
Current assets	113.7		133.8
Non-current assets	903.8		941.3
Total assets	1,017.5		1,075.1
Current liabilities	5.8		7.8
Long-term debt of consolidated investment products	0		0
Other non-current liabilities	0		0
Total liabilities	5.8		7.8
Retained earnings appropriated for investors in consolidated investment products	0		0
Other equity attributable to common shareholders	43.1		38.1
Equity attributable to noncontrolling interests in consolidated entities	968.6		1,029.2
Total liabilities and equity	1,017.5		1,075.1
VIE Adjustments [Member]
Current assets	(29.9)	[1]	(22.3)	[1]
Non-current assets	(92.5)	[1]	(61.0)	[1]
Total assets	(122.4)	[1]	(83.3)	[1]
Current liabilities	(29.9)	[1]	(22.3)	[1]
Long-term debt of consolidated investment products	(50.4)	[1]	(22.8)	[1]
Other non-current liabilities	0	[1]	0	[1]
Total liabilities	(80.3)	[1]	(45.1)	[1]
Retained earnings appropriated for investors in consolidated investment products	0	[1]	0	[1]
Other equity attributable to common shareholders	(42.1)	[1]	(38.2)	[1]
Equity attributable to noncontrolling interests in consolidated entities	0	[1]	0	[1]
Total liabilities and equity	$ (122.4)	[1]	$ (83.3)	[1]

[1] Adjustments include the elimination of intercompany transactions between the company and its consolidated investment products, primarily the elimination of the company's equity at risk recorded as investments by the company (before consolidation) against either equity (private equity and real estate partnership funds) or subordinated debt (CLOs) of the funds.