Investment Income And Gains And Losses (Change In Net Unrealized Gains (Losses)) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Total	$ 380		$ 796
Deferred income tax charged (credited)	122		213
Change in unrealized gains (losses), net	258	[1]	583	[1]
Fixed-Maturity Investments [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Total	386		749
Other Long Term Investments [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Total	(6)		47
Variable Interest Entities [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Net unrealized gains due to transition adjustments			$ 266

[1] The annual change as of December 31, 2010 included $266 million of net unrealized gains due to the transition adjustment for the adoption of the accounting principles for consolidation of VIEs.