Investments - Valuation Reserves for Commercial Mortgage Loans (Details) (Mortgage Loans on Real Estate [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2014	Mar. 31, 2013
Mortgage Loans on Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Increase (Decrease)	$ 0	$ 0

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