Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Consolidated Statements of Comprehensive Income
Net Income	$ 1,545	$ 1,678	$ 2,174
Other Comprehensive Income (Loss), Net of Tax
Change in Unrealized Appreciation of Investments	275	615	69
Change in Unrealized Other-Than-Temporary Impairment Losses on Investments	2	1	7
Foreign Currency Translation Gains (Losses)	(11)	4	(18)
Change in Postretirement Benefit Costs Not Yet Recognized in Net Income	(30)	(215)	12
Total Other Comprehensive Income, Net of Tax	236	405	70
COMPREHENSIVE INCOME	$ 1,781	$ 2,083	$ 2,244