Earnings Per Share (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Antidilutive Options Table [Abstract]
Antidilutive options	3,900,000	3,900,000	3,400,000	3,600,000
Statement Line Items [Line Items]
Shareholders' net income	$ 466	$ 183	$ 1,217	$ 987
Shares (in thousands):
EPS	$ 1.64	$ 0.68	$ 4.27	$ 3.67
Earnings Per Share Text Details [Abstract]
Common shares held in Treasury	79,439,106	80,697,257	79,439,106	80,697,257
Earnings Per Share Basic Member
Statement Line Items [Line Items]
Shareholders' net income	466	183	1,217	987
Shares (in thousands):
Weighted average	284,891,000	268,569,000	285,247,000	269,163,000
Total shares	284,891,000	268,569,000	285,247,000	269,163,000
EPS	$ 1.64	$ 0.68	$ 4.27	$ 3.67
Effect Of Dilution [Member]
Shares (in thousands):
Common stock equivalents	4,984,000	3,491,000	4,560,000	3,721,000
Total shares	4,984,000	3,491,000	4,560,000	3,721,000
EPS	$ (0.03)	$ (0.01)	$ (0.07)	$ (0.05)
Earnings Per Share Diluted [Member]
Statement Line Items [Line Items]
Shareholders' net income	$ 466	$ 183	$ 1,217	$ 987
Shares (in thousands):
Weighted average	284,891,000	268,569,000	285,247,000	269,163,000
Common stock equivalents	4,984,000	3,491,000	4,560,000	3,721,000
Total shares	289,875,000	272,060,000	289,807,000	272,884,000
EPS	$ 1.61	$ 0.67	$ 4.20	$ 3.62