Investments (Details 46) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Variable Interest Entity [Line Items]
Total Assets	$ 84,450	$ 86,010
Total Liabilities	86,442	88,167
Real estate joint ventures [Member]
Variable Interest Entity [Line Items]
Total Assets	103	61
Total Liabilities	119	79
Other limited partnership interests [Member]
Variable Interest Entity [Line Items]
Total Assets	4,391	4,340
Total Liabilities	6,003	6,084
Trading securities [Member]
Variable Interest Entity [Line Items]
Total Assets	708	671
Total Liabilities	708	671
Mortgage loans, net [Member]
Variable Interest Entity [Line Items]
Total Assets	356	456
Total Liabilities	356	456
Other invested assets [Member]
Variable Interest Entity [Line Items]
Total Assets	839	799
Total Liabilities	1,203	1,194
U.S. corporate securities [Member]
Variable Interest Entity [Line Items]
Total Assets	2,846	2,911
Total Liabilities	2,846	2,911
Foreign corporate securities [Member]
Variable Interest Entity [Line Items]
Total Assets	2,053	2,087
Total Liabilities	2,053	2,087
RMBS [Member]
Variable Interest Entity [Line Items]
Total Assets	41,279	42,637
Total Liabilities	41,279	42,637
CMBS [Member]
Variable Interest Entity [Line Items]
Total Assets	18,732	19,069
Total Liabilities	18,732	19,069
ABS [Member]
Variable Interest Entity [Line Items]
Total Assets	13,143	12,979
Total Liabilities	$ 13,143	$ 12,979