Investments (excluding Consolidated Investment Entities) - Allowance for Loan Losses (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012
Investments, Debt and Equity Securities [Abstract]
Collective valuation allowance for losses, beginning of period	$ 3.9	$ 4.4
Addition to/(release of) allowance for losses	(0.1)	(0.5)
Collective valuation allowance for losses, end of period	$ 3.8	$ 3.9

The increase (decrease) in the allowance for credit losses related to financing receivables.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=28368275&loc=SL6953423-111524

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesPeriodIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration