Investments (Unconsolidated Variable Interest Entities) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Variable Interest Entity [Line Items]
Total Assets	$ 82,384	$ 84,541
Total Liabilities	84,190	86,334
Real estate joint ventures [Member]
Variable Interest Entity [Line Items]
Total Assets	114	150
Total Liabilities	119	157
Other limited partnership interests [Member]
Variable Interest Entity [Line Items]
Total Assets	4,717	4,436
Total Liabilities	6,259	5,908
Trading securities [Member]
Variable Interest Entity [Line Items]
Total Assets	603	563
Total Liabilities	603	563
Mortgage loans, net [Member]
Variable Interest Entity [Line Items]
Total Assets	199	351
Total Liabilities	199	351
Other invested assets [Member]
Variable Interest Entity [Line Items]
Total Assets	1,210	1,117
Total Liabilities	1,469	1,431
Structured securities (RMBS, CMBS, and ABS) [Member]
Variable Interest Entity [Line Items]
Total Assets	70,358	72,605
Total Liabilities	70,358	72,605
US and foreign corporate securities [Member]
Variable Interest Entity [Line Items]
Total Assets	5,150	5,287
Total Liabilities	5,150	5,287
Non-redeemable preferred stock [Member]
Variable Interest Entity [Line Items]
Total Assets	33	32
Total Liabilities	$ 33	$ 32