Common Stockholders' Equity

12 Months Ended

Dec. 31, 2011

Equity [Abstract]

Common Stockholders' Equity

Common Stockholders’ Equity

The weighted average number of shares used in the computation of net income per share was as follows:

(Amounts in thousands)	2011	2010	2009
Basic	139,688	148,752	160,357
Diluted	145,672	155,081	166,574

Treasury shares have been excluded from average outstanding shares from the date of acquisition. The difference in calculating basic and diluted net income per share is attributable entirely to the dilutive effect of stock-based compensation plans.

Changes in shares of common stock outstanding, net of treasury shares, are presented below. Shares of common stock issued and outstanding do not include shares related to unissued restricted stock units and unexercised stock options.

(Amounts in thousands)	2011		2010		2009
Balance, beginning of year	141,010		156,552		161,467
Shares issued	2,702		2,272		1,467
Shares repurchased	(6,192	)	(17,814	)	(6,382	)
Balance, end of year	137,520		141,010		156,552