Amount of transfers of financial instrument classified as a liability into level 3 of the fair value hierarchy.

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Amount of gain (loss) recognized in the income statement for financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of sale of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of transfer of financial instrument classified as an asset into level 3 of the fair value hierarchy.

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Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Consolidated Investment Entities (Fair Value Measurements for Level 3 Assets and Liabilities) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2014 Consolidated investment entities Measured at fair value on a recurring basis Level 3	Mar. 31, 2013 Consolidated investment entities Measured at fair value on a recurring basis Level 3	Mar. 31, 2014 Consolidated investment entities VIEs Loans Receivable Measured at fair value on a recurring basis Level 3	Mar. 31, 2013 Consolidated investment entities VIEs Loans Receivable Measured at fair value on a recurring basis Level 3	Mar. 31, 2014 Consolidated investment entities VIEs Collateralized Debt Obligations Measured at fair value on a recurring basis Level 3	Mar. 31, 2013 Consolidated investment entities VIEs Collateralized Debt Obligations Measured at fair value on a recurring basis Level 3	Mar. 31, 2014 Consolidated investment entities VOEs Limited Partnerships Measured at fair value on a recurring basis Level 3	Mar. 31, 2013 Consolidated investment entities VOEs Limited Partnerships Measured at fair value on a recurring basis Level 3	Mar. 31, 2014 Collateralized Debt Obligations Consolidated investment entities VIEs	Dec. 31, 2013 Collateralized Debt Obligations Consolidated investment entities VIEs	Mar. 31, 2014 Loans Receivable Consolidated investment entities VIEs	Dec. 31, 2013 Loans Receivable Consolidated investment entities VIEs
Variable Interest Entity [Line Items]
Fair Value, Assets, beginning balance		$ 2,759.6	$ 2,931.2	$ 25.5	$ 0			$ 2,734.1	$ 2,931.2			$ 25.0	$ 25.5
Gains (Losses) Included in the Condensed Consolidated Statement of Operations		(0.4)	(15.8)	0.2	0			(0.6)	(15.8)
Purchases		5.1	65.9	0	0			5.1	65.9
Sales		(0.7)	(0.6)	(0.7)	0			0	(0.6)
Transfers in to Level 3	13.9	13.9	0	0	0			13.9	0
Transfers out of Level 3		0	0	0	0			0	0
Fair Value, Assets, ending balance		2,777.5	2,980.7	25.0	0			2,752.5	2,980.7			25.0	25.5
Liabilities, Fair Value, beginning balance		5,161.6	3,829.4			5,161.6	3,829.4			5,525.5	5,161.6
Gains (Losses) Included in the Condensed Consolidated Statement of Operations		1.1	6.7			1.1	6.7
Purchases		409.4	612.9			409.4	612.9
Sales		(46.6)	(0.9)			(46.6)	(0.9)
Transfer in to Level 3		0	0			0	0
Transfer out of Level 3		0	0			0	0
Liabilities, Fair Value, ending balance		$ 5,525.5	$ 4,448.1			$ 5,525.5	$ 4,448.1			$ 5,525.5	$ 5,161.6