Stock-Based Compensation

9 Months Ended

Sep. 30, 2017

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

Stock-Based Compensation

STOCK-BASED COMPENSATION

For employee awards, equity classified stock-based compensation cost is measured at the service inception date or the grant date, based on the estimated achievement of certain performance metrics or the fair value of the award, and is recognized as expense or capitalized as a component of property, plant and equipment over the requisite service period.

Pretax stock-based compensation costs, the tax benefit associated with stock-based compensation expense and stock-based compensation costs capitalized are included in the following table.

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
(in millions)	2017		2016		2017		2016
Restricted stock unit awards	$	10	$	8	$	30	$	25
Performance awards	7		4		20		14
Pretax stock-based compensation cost	$	17	$	12	$	50	$	39
Tax benefit associated with stock-based compensation expense	$	6	$	5	$	18	$	14
Stock-based compensation costs capitalized	1		—		2		2

Prior to Duke Energy acquiring Piedmont, Piedmont had an incentive compensation plan for eligible officers and other participants. Piedmont's total pretax stock-based compensation costs were approximately $2 million and $5 million for the three and nine months ended September 30, 2016, respectively. The tax benefit associated with Piedmont's stock-based compensation expense for the three and nine months ended September 30, 2016, was immaterial.