Separate Accounts, Death Benefits and Other Insurance Benefit Features (Details 2) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Variable separate accounts	$ 72,895	$ 68,988
Equity securities (including mutual funds) [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Variable separate accounts	65,862	61,742
Cash and cash equivalents [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Variable separate accounts	$ 7,033	$ 7,516