Summary of Significant Accounting Policies (Details) (USD $) In Billions, unless otherwise specified			12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Hedge funds	Dec. 31, 2012 Private equity/debt funds, real estate funds and tax credit funds
Investments
Policy loans	$ 1.14	$ 1.15
Period over which recognition of income on funds is delayed			1 month	3 months

Carrying amount of loans made to policyholders against the cash surrender value (CSV) or other policyholder funds, and secured by the CSV, policyholder funds or the death benefit provided by the insurance contracts.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Subparagraph e

-Article 7

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.(a),1(e))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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