Earnings per share (Tables)

12 Months Ended

Dec. 31, 2011

Notes To Financial Statements [Abstract]

Earnings per share reconciliation

	Year ended December 31,		2011		2010		2009
Basic earnings per share		$	5.45	$	4.51	$	3.95
Diluted earnings per share		$	5.41	$	4.48	$	3.92
The following table provides a reconciliation between basic and diluted earnings per share:
In millions	Year ended December 31,		2011		2010		2009
Net income		$	2,457	$	2,104	$	1,854
Weighted-average shares outstanding			451.1		466.3		469.2
Effect of stock options			3.3		3.8		4.3
Weighted-average diluted shares outstanding			454.4		470.1		473.5