Consolidated Statements of Shareholders' Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Paid-In-Surplus [Member]	Retained Earnings [Member]	Unrealized Appreciation of Investments Including Unrealized Other-Than-Temporary Impairment Losses [Member]	Postretirement Benefit Costs Not Yet Recognized in Net Income [Member]	Foreign Currency Translation Gains (Losses) [Member]	Accumulated Other Comprehensive Income [Member]	Treasury Stock, at Cost [Member]
Balance, Beginning of Year at Dec. 31, 2013			$ 171	$ 21,902	$ 1,225	$ (253)	$ 63		$ (7,383)
Net Income	$ 948			948
Repurchase of Shares									(784)
Changes Related to Stock-Based Employee Compensation (includes tax benefit of $3 and $14)			(42)
Change During Period, Net of Tax	469				473	11	(15)
Dividends Declared (per share $1.14 and $1.00)				(246)
Shares Issued Under Stock-Based Employee Compensation Plans									56
Balance, End of Period at Jun. 30, 2014	16,498	$ 372	129	22,604	1,698	(242)	48	$ 1,504	(8,111)
Balance, Beginning of Year at Dec. 31, 2014	16,296		171	23,520	1,753	(589)	(54)		(8,877)
Net Income	869			869
Repurchase of Shares									(604)
Changes Related to Stock-Based Employee Compensation (includes tax benefit of $3 and $14)			(15)
Change During Period, Net of Tax	(403)				(266)	24	(161)
Dividends Declared (per share $1.14 and $1.00)				(264)
Shares Issued Under Stock-Based Employee Compensation Plans									39
Balance, End of Period at Jun. 30, 2015	$ 15,918	$ 372	$ 156	$ 24,125	$ 1,487	$ (565)	$ (215)	$ 707	$ (9,442)