Stock-Based Compensation

3 Months Ended

Mar. 31, 2013

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-Based Compensation

Stock-Based Compensation

We issue stock-based incentive awards to our eligible employees and Directors under the 2002 Employee Stock Incentive Plan and a Director Deferred Stock Ownership Plan. No further awards may be granted under the 1993 Employee Stock Incentive Plan and any remaining outstanding options under the 1993 Employee Stock Incentive Plan expired in the first quarter of 2013. The 2002 Employee Stock Incentive Plan permits the granting of nonqualified stock options, stock appreciation rights, performance stock, restricted stock and other stock-based awards.

Stock-based compensation for the three months ended March 31 is as follows:

(in millions)	2013		2012
Stock option expense	$	2	$	5
Restricted stock and unit awards expense	19		12
Total stock-based compensation expense	$	21	$	17

As of March 31, 2013 and December 31, 2012, we issued 2.1 million and 8.4 million common shares, respectively, upon exercise of certain stock options outstanding.