Stock-Based Compensation

3 Months Ended

Mar. 31, 2019

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

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. 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. In 2018, we also made a one-time issuance of incentive stock options under the 2002 Employee Stock Incentive Plan to replace Kensho employees' stock options that were assumed in connection with our acquisition of Kensho in April of 2018.

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



(in millions)	2019		2018
Stock option expense	$	—	$	1
Restricted stock and unit awards expense	12		12
Total stock-based compensation expense	$	12	$	13

Total unrecognized compensation expense related to unvested stock option awards and unvested restricted stock and unit awards as of March 31, 2019 was $1 million and $58 million, respectively, which is expected to be recognized over a weighted average period of 1.3 years and 1.7 years, respectively.