Stockholders' equity (Tables)

6 Months Ended

Jun. 30, 2011

Stockholders' equity [Abstract]

Summary of activity under a stock repurchase program

	2011				2010
	Shares		Dollars		Shares		Dollars
First quarter		—	$	—		29.1	$	1,684
Second quarter		12.9		732		10.3		616
		12.9	$	732		39.4	$	2,300