Investments (Details 46) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Variable Interest Entity [Line Items]
Total Assets	$ 86,829	$ 86,010
Total Liabilities	88,715	88,167
Real estate joint ventures [Member]
Variable Interest Entity [Line Items]
Total Assets	119	61
Total Liabilities	131	79
Other limited partnership interests [Member]
Variable Interest Entity [Line Items]
Total Assets	4,619	4,340
Total Liabilities	6,194	6,084
Trading securities [Member]
Variable Interest Entity [Line Items]
Total Assets	573	671
Total Liabilities	573	671
Mortgage loans, net [Member]
Variable Interest Entity [Line Items]
Total Assets	361	456
Total Liabilities	361	456
Other invested assets [Member]
Variable Interest Entity [Line Items]
Total Assets	969	799
Total Liabilities	1,268	1,194
U.S. corporate securities [Member]
Variable Interest Entity [Line Items]
Total Assets	2,802	2,911
Total Liabilities	2,802	2,911
Foreign corporate securities [Member]
Variable Interest Entity [Line Items]
Total Assets	2,319	2,087
Total Liabilities	2,319	2,087
RMBS [Member]
Variable Interest Entity [Line Items]
Total Assets	40,591	42,637
Total Liabilities	40,591	42,637
CMBS [Member]
Variable Interest Entity [Line Items]
Total Assets	19,440	19,069
Total Liabilities	19,440	19,069
ABS [Member]
Variable Interest Entity [Line Items]
Total Assets	15,005	12,979
Total Liabilities	15,005	12,979
Non-redeemable preferred stock [Member]
Variable Interest Entity [Line Items]
Total Assets	31	0
Total Liabilities	$ 31	$ 0