Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net Income	$ 601	$ 594	$ 1,470	$ 1,542
Other Comprehensive Income (Loss), Net of Tax
Change in Unrealized Appreciation of Investments	(19)	(46)	(285)	427
Change in Postretirement Benefit Costs Not Yet Recognized in Net Income	11	6	35	17
Foreign Currency Translation Losses	(38)	(26)	(199)	(41)
Total Other Comprehensive Income (Loss) Net of Tax	(46)	(66)	(449)	403
Comprehensive Income	$ 555	$ 528	$ 1,021	$ 1,945