Investments of Operating Entities and Consolidated Funds - Other (Details) (Operating Entities) In Millions, unless otherwise specified	9 Months Ended
Dec. 31, 2011 USD ($) entities	Dec. 31, 2011 EUR (€) entities
Significant Acquisitions and Disposals [Line Items]
Reinsurance companies acquired, not business combination	2	2
Purchase price for reinsurance companies acquired, not business combination	$ 331.8	€ 234.8

The value of all consideration given or received by the Entity in the significant acquisition or disposal.

No definition available.

Name:	us-gaap_SignificantAcquisitionsAndDisposalsAcquisitionCostsOrSaleProceeds
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant