Common and Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Common: Par value $.25, 600,000,000 shares authorized
Outstanding - January 1	259,276,000	275,526,000	285,829,000
Shares Issued For Benefit Plans In Period	2,751,000	2,284,000	3,319,000
Repurchase of common stock	(5,483,000)	(18,534,000)	(13,622,000)
Outstanding - December 31	256,544,000	259,276,000	275,526,000
Treasury stock	39,601,000	36,869,000	90,619,000
Issued - December 31	296,145,000	296,145,000	366,145,000
Common Stock, par value and shares authorized
Common stock, par value per share	$ 0.25	$ 0.25	$ 0.25
Common stock shares authorized	600,000,000	600,000,000	600,000,000
Payments For Repurchase Of Common Stock	$ 671	$ 1,612	$ 1,003
Shares of treasury stock retired		70,000,000
Retirement of treasury stock effect on shareholders' equity		$ 0
Preferred Stock [Abstract]
Preferred Stock, Shares Authorized	25,000,000	25,000,000	25,000,000
Preferred Stock, Par Value Per Share	$ 1	$ 1	$ 1
Preferred Stock, Shares Outstanding	0	0	0
Shareholders' Equity [Member]
Retirement of treasury stock effect on shareholders' equity		$ 0