Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement Of Income And Comprehensive Income [Abstract]
Net Income	$ 449	$ 656
Other Comprehensive Income (Loss), Net of Tax
Change in Unrealized Appreciation of Investments	235	4
Change in Postretirement Benefit Costs Not Yet Recognized in Net Income	6	17
Foreign Currency Translation Losses	(19)	(50)
Total Other Comprehensive Income (Loss) Net of Tax	222	(29)
Comprehensive Income	$ 671	$ 627