Reinsurance (Components of Life Insurance Inforce) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Life Insurance Inforce, Direct	$ 6,528	$ 8,015	$ 9,159
Life Insurance Inforce, Assumed
Life Insurance Inforce, Ceded	6,515	8,001	9,144
Life Insurance Inforce, Net	$ 13	$ 14	$ 15