Shareholders' Equity (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Jun. 07, 2012
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	0
Common stock, outstanding (in shares)	353,674,248	356,437,880
Preferred stock, outstanding (in shares)	0	0
Stock repurchased (in shares)	9,100,000
Repurchased shares - average price	$ 66
Shares remaining under a prior authorization	10,900,000			2,400,000
Repurchase of shares authorized				10,000,000
Authorized shares for repurchase as a percentage of total shares outstanding	3.00%
Dividends declared per share	$ 2.04	$ 1.88	$ 1.68
Dividends paid in cash	$ 893	$ 673	$ 631
Restricted Stock [Member]
Class of Stock [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	2,377,354