Shareholders' Equity (Details) (USD $)	1 Months Ended	3 Months Ended				24 Months Ended
	Apr. 30, 2012	Mar. 31, 2014		Mar. 31, 2013		Mar. 31, 2014
Common Stock Programs
Total cost of shares purchased		$ 600,000,000
Weighted average shares outstanding
Shares for basic earnings per share (in shares)		303,500,000	[1]	316,400,000	[1]
Common stock equivalents (in shares)		3,700,000		3,600,000
Shares for diluted earnings per share (in shares)		307,200,000		320,000,000
Number of participating securities (in shares)		3,400,000		4,200,000
Number of shares excluded from the calculation of diluted earnings per share		0		200,000
2012 - Share Repurchase Program [Member]
Common Stock Programs
Share repurchase authorization limit	5,000,000,000
Shares purchased (in shares)		7,200,000		5,000,000		43,500,000
Average price per share of stock repurchased		$ 83.45		$ 59.82
Total cost of shares purchased		600,000,000		300,000,000		2,700,000,000
Share repurchase, remaining authorization limit		$ 2,300,000,000

[1] Includes 3.4 million and 4.2 million of participating securities for the three months ended March 31, 2014 and 2013, respectively