Investments (Unconsolidated Variable Interest Entities) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Variable Interest Entity [Line Items]
Carrying Amount	$ 51,678	$ 47,858
Total Liabilities	53,131	49,317
Real estate joint ventures
Variable Interest Entity [Line Items]
Carrying Amount	52	31
Total Liabilities	74	31
Other limited partnership interests
Variable Interest Entity [Line Items]
Carrying Amount	3,722	3,168
Total Liabilities	4,833	4,273
Other invested assets
Variable Interest Entity [Line Items]
Carrying Amount	1,683	1,498
Total Liabilities	2,003	1,852
Structured securities (RMBS, CMBS, and ABS) [Member]
Variable Interest Entity [Line Items]
Carrying Amount	44,302	40,910
Total Liabilities	44,302	40,910
U.S. and foreign corporate
Variable Interest Entity [Line Items]
Carrying Amount	1,919	2,251
Total Liabilities	$ 1,919	$ 2,251