Common and Preferred Stock (Details) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended		12 Months Ended			14 Months Ended
	Feb. 27, 2013	Feb. 28, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Feb. 28, 2013
Schedule Of Issued Shares Parantheticals [Abstract]
Common stock par value			$ 0.25	$ 0.25
Common Stock Shares Authorized			600,000,000	600,000,000
Common And Preferred Stock Text Details [Abstract]
Preferred Stock, Shares Outstanding			0
Preferred Stock, Shares Authorized			25,000,000
Preferred Stock, Par or Stated Value Per Share			$ 1
600,000 shares authorized
Outstanding - January 1			285,533,000	271,880,000		285,533,000
Stock Issued During Period, Shares, New Issues			0	15,200,000
Shares Issued For Benefit Plans In Period			4,695,000	3,735,000
Repurchase of common stock			(4,399,000)	(5,282,000)		(4,399,000)
Outstanding - December 31			285,829,000	285,533,000	271,880,000
Treasury stock			80,316,000	80,612,000
Issued - December 31			366,145,000	366,145,000
Common Stock Issuance Text Details [Abstract]
Cost of Common Stock Issued Per Share				$ 42.75
Proceeds From Issuance Of Common Stock Net				$ 629
Proceeds From Issuance Of Common Stock Gross				650
Stock Repurchase Program, Remaining Authorized Repurchase Amount		815
Payments For Repurchase Of Common Stock			208	225	201	208
Stock Repurchase Program, Authorized Amount Increase	$ 500