Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement Of Income And Comprehensive Income [Abstract]
Net Income	$ 2,345	$ 1,545	$ 1,678
Other Comprehensive Income (Loss), Net of Tax
Change in Unrealized Appreciation of Investments	(788)	275	615
Change in Unrealized Other-Than-Temporary Impairment Losses on Investments		2	1
Change in Postretirement Benefit Costs Not Yet Recognized in Net Income	464	(30)	(215)
Foreign Currency Translation Gains (Losses)	(72)	(11)	4
Total Other Comprehensive Income (Loss) Net of Tax	(396)	236	405
COMPREHENSIVE INCOME	$ 1,949	$ 1,781	$ 2,083