Stock-Based Compensation

6 Months Ended

Jun. 30, 2018

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 periods ended June 30 is as follows:



(in millions)	Three Months				Six Months
	2018		2017		2018		2017
Stock option expense	$	2	$	—	$	2	$	2
Restricted stock and unit awards expense	32		21		44		39
Total stock-based compensation expense	$	34	$	21	$	46	$	41

During the six months ended June 30, 2018, the Company granted 0.2 million shares of employee stock options, which had a weighted average grant date value of $128.46 per share based on the lattice-based option-pricing model. The Company also granted 0.7 million shares of restricted stock and unit awards, which had a weighted average grant date fair value of $169.77 per share.

Total unrecognized compensation expense related to unvested stock option awards and unvested restricted stock and unit awards as of June 30, 2018 was $3 million and $125 million, respectively, which is expected to be recognized over a weighted average period of 2.6 years and 2.2 years, respectively.