Earnings Per Share, Share Repurchases and Dividends on Common Stock (Unaudited) (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	3 Months Ended				9 Months Ended		18 Months Ended	0 Months Ended		6 Months Ended	9 Months Ended
	Sep. 30, 2012	Mar. 31, 2012	Sep. 30, 2011	Mar. 31, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 19, 2012 Jun 2010 Share Repurchase Program Original Authorization [Member]	Apr. 26, 2011 Jun 2010 Share Repurchase Program Original Authorization [Member]	Jun. 30, 2010 Jun 2010 Share Repurchase Program Original Authorization [Member]	Sep. 30, 2012 Jun 2010 Share Repurchase Program Original Authorization [Member]		Sep. 30, 2011 Jun 2010 Share Repurchase Program Original Authorization [Member]
Share Repurchase [Line Items]
Dilutive effect of of stock awards granted to employees under stock-based compensation plans	4.9		4.4		4.6	4.8
Anti-dilutive shares excluded from computation of earnings per share	1.3		3.6		2.7	2.8
Share Repurchases (Table Amounts)
Amount Authorized										$ 2,000,000,000	$ 5,350,000,000	[1]
Total Shares Retired							54.0				57.8	[1]
Average Price Per Share											$ 58.46	[1],[2]
Shares Repurchased											13.6	[1]	28.4	[1]
Share Repurchased Amount											3,400,000,000
Share Repurchases (Amounts in Paragraphs)
Increase authorized								2,000,000,000	4,000,000,000
Amount remaining under authorization for share repurchases											$ 2,000,000,000
Share Repurchase Limit Due to IRS Action	34			88	34		34
Period Of Share Repurchase Limit				2 years
Common stock dividends per share, declared	$ 0.55	$ 0.50	$ 0.50	$ 0.47	$ 1.60	$ 1.47

[1] In June 2010, our board of directors authorized a share repurchase program of up to $2.0 billion of the company’s common stock. Following this initial authorization, our board of directors increased the remaining repurchase authorization to $4.0 billion in April 2011 and again increased the remaining repurchase authorization to $2.0 billion in September 2012. As of September 30, 2012, our repurchases under the program totaled $3.4 billion, and $2.0 billion remained under this share repurchase authorization. The repurchase program will expire when we have used all authorized funds for repurchase.

[2] Includes commissions paid.