Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Consolidated Statements of Comprehensive Income [Abstract]
Net Income	$ 1,678	$ 2,174	$ 2,183
Other Comprehensive Income (Loss), Net of Tax
Change in Unrealized Appreciation of Investments	615	69	1,223
Change in Unrealized Other-Than-Temporary Impairment Losses on Investments	1	7	(6)
Foreign Currency Translation Gains (Losses)	4	(18)	170
Change in Postretirement Benefit Costs Not Yet Recognized in Net Income	(215)	12	98
Total Other Comprehensive Income, Net of Tax	405	70	1,485
COMPREHENSIVE INCOME	$ 2,083	$ 2,244	$ 3,668