Shareholders' Equity (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Oct. 02, 2013	Dec. 31, 2013 Restricted Stock [Member]	Feb. 05, 2014 Subsequent Event [Member]	Jan. 24, 2014 Subsequent Event [Member]
Class of Stock [Line Items]
Authorized capital stock, common stock (in shares)	500,000,000
Common stock, par value	$ 1
Authorized capital stock, preferred stock (in shares)	50,000,000
Preferred stock, par value	$ 1
Common stock, issued (in shares)	481,880,634	481,880,634
Common stock, outstanding (in shares)	353,402,794	353,674,248
Unvested restricted stock (in shares)					1,947,273
Preferred stock, outstanding (in shares)	0	0
Stock repurchased (in shares)	9,400,000
Repurchased shares - average price	$ 78
Shares remaining under a prior authorization	11,400,000			1,400,000
Repurchase of shares authorized				10,000,000		20,000,000	11,400,000
Authorized shares for repurchase as a percentage of total shares outstanding	3.00%
Dividends declared per share	$ 2.24	$ 2.04	$ 1.88
Dividends paid	$ 591	$ 893	$ 673