Shareholders' Equity (Details) (USD $)	3 Months Ended				36 Months Ended
	Mar. 31, 2015		Mar. 31, 2014		Mar. 31, 2015	Apr. 30, 2012	Nov. 30, 2014
Common Stock Programs
Total cost of shares purchased	$ 250,000,000
Weighted average shares outstanding
Shares for basic earnings per share (in shares)	284,200,000	[1]	303,500,000	[1]
Common stock equivalents (in shares)	2,900,000		3,700,000
Shares for diluted earnings per share (in shares)	287,100,000		307,200,000
Net income, attributable to participating securities	2,000,000		3,000,000
Number of participating securities (in shares)	2,500,000		3,400,000
Number of shares excluded from the calculation of diluted earnings per share	0		0
2012 - Share Repurchase Program [Member]
Common Stock Programs
Share repurchase authorization limit						5,000,000,000.0
Shares purchased (in shares)	2,500,000		7,200,000		64,600,000
Average price per share of stock repurchased	$ 100.15		$ 83.45
Total cost of shares purchased	250,000,000		600,000,000		4,600,000,000
Share repurchase, remaining authorization limit	5,400,000,000				5,400,000,000
Share Repurchase Program of 2014 [Member]
Common Stock Programs
Share repurchase authorization limit							$ 5,000,000,000.0

[1] Includes 2.5 million and 3.4 million of participating securities for the three months ended March 31, 2015 and 2014, respectively.