Shareholders' Equity (Details) (USD $)	1 Months Ended	3 Months Ended				6 Months Ended				27 Months Ended
	Apr. 30, 2012	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014
Common Stock Programs
Total cost of shares purchased						$ 1,250,000,000
Weighted average shares outstanding
Shares for basic earnings per share (in shares)		298,500,000	[1]	313,700,000	[1]	301,000,000	[1]	315,000,000	[1]
Common stock equivalents (in shares)		3,100,000		3,400,000		3,400,000		3,600,000
Shares for diluted earnings per share (in shares)		301,600,000		317,100,000		304,400,000		318,600,000
Number of participating securities (in shares)		3,000,000		4,000,000		3,200,000		4,100,000
Number of shares excluded from the calculation of diluted earnings per share		0		0		0		400,000.0
2012 - Share Repurchase Program [Member]
Common Stock Programs
Share repurchase authorization limit	5,000,000,000
Shares purchased (in shares)		7,400,000		3,500,000		14,600,000		8,500,000		50,900,000
Average price per share of stock repurchased		$ 87.67		$ 64.53		$ 85.59		$ 61.75
Total cost of shares purchased		650,000,000		225,000,000		1,300,000,000		525,000,000		3,400,000,000
Share repurchase, remaining authorization limit						$ 1,600,000,000

[1] Includes 3.0 million and 4.0 million of participating securities for the three months ended June 30, 2014 and 2013, respectively, and 3.2 million and 4.1 million of participating securities for the six months ended June 30, 2014 and 2013, respectively.