Investments and Derivative Instruments (Details 11) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012		Dec. 31, 2011
Variable Interest Entity [Line Items]
Document Period End Date	Sep. 30, 2012
Variable Interest Entities Primary Beneficiary
Total Liabilities	$ 420		$ 471
Variable Interest Entity Assets Included in Limited Partnerships and Other Alternative Investments	6		7
Consolidated VIEs [Member]
Variable Interest Entities Primary Beneficiary
Total Assets	616		498
Maximum Exposure to Loss	178	[1]	36	[1]
Collateralized Debt Obligations [Member] | Consolidated VIEs [Member]
Variable Interest Entities Primary Beneficiary
Total Assets	446	[2]	491	[2]
Total Liabilities	420	[2],[3]	471	[2],[3]
Maximum Exposure to Loss	15	[1],[2]	29	[1],[2]
Investment Fund [Member] | Consolidated VIEs [Member]
Variable Interest Entities Primary Beneficiary
Total Assets	164	[4]	0	[4]
Total Liabilities	0	[3],[4]	0	[3],[4]
Maximum Exposure to Loss	157	[1],[4]	0	[1],[4]
Limited partnerships [Member] | Consolidated VIEs [Member]
Variable Interest Entities Primary Beneficiary
Total Liabilities	0	[3]	0	[3]
Maximum Exposure to Loss	$ 6	[1]	$ 7	[1]

[1] The maximum exposure to loss represents the maximum loss amount that the Company could recognize as a reduction in net investment income or as a realized capital loss and is the cost basis of the Company’s investment.

[2] Total assets included in fixed maturities, AFS, and fixed maturities, FVO, in the Company’s Condensed Consolidated Balance Sheets.

[3] Included in other liabilities in the Company’s Condensed Consolidated Balance Sheets.

[4] Total assets included in fixed maturities, AFS, and short-term investments in the Company’s Condensed Consolidated Balance Sheets.