Investments (Unconsolidated Variable Interest Entities) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Variable Interest Entity [Line Items]
Total Assets	$ 81,167	$ 84,541
Total Liabilities	82,973	86,334
Real estate joint ventures [Member]
Variable Interest Entity [Line Items]
Total Assets	115	150
Total Liabilities	121	157
Other limited partnership interests [Member]
Variable Interest Entity [Line Items]
Total Assets	4,798	4,436
Total Liabilities	6,369	5,908
Trading securities [Member]
Variable Interest Entity [Line Items]
Total Assets	629	563
Total Liabilities	629	563
Mortgage loans, net [Member]
Variable Interest Entity [Line Items]
Total Assets	185	351
Total Liabilities	185	351
Other invested assets [Member]
Variable Interest Entity [Line Items]
Total Assets	1,290	1,117
Total Liabilities	1,519	1,431
Structured securities (RMBS, CMBS, and ABS) [Member]
Variable Interest Entity [Line Items]
Total Assets	69,359	72,605
Total Liabilities	69,359	72,605
US and foreign corporate securities [Member]
Variable Interest Entity [Line Items]
Total Assets	4,759	5,287
Total Liabilities	4,759	5,287
Non-redeemable preferred stock [Member]
Variable Interest Entity [Line Items]
Total Assets	32	32
Total Liabilities	$ 32	$ 32