Shareholders' Equity (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended	12 Months Ended
	Oct. 29, 2007	Dec. 31, 2012	Dec. 31, 2011
Stockholders' Equity Note [Abstract]
Amount approved to repurchase, shares, maximum	$ 7,000
Amount approved to repurchase, shares, remaining		$ 3,610
Common Stock, Shares Authorized		1,200,000,000	1,200,000,000
Preferred shares, authorized		20,000,000	20,000,000