Share-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2018

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

Summary of the changes in unvested restricted stock

A summary of the changes in unvested restricted stock during the Current Period is presented below:

	Shares of Unvested Restricted Stock		Weighted Average Grant Date Fair Value Per Share
	(in thousands)
Unvested restricted stock as of January 1, 2018	13,178		$	6.37
Granted	5,776		$	3.77
Vested	(5,782	)	$	7.67
Forfeited	(1,376	)	$	6.09
Unvested restricted stock as of September 30, 2018	11,796		$	4.49

Weighted average assumptions to estimate grant date fair value of the stock options granted

We utilized a Monte Carlo simulation for the TSR performance measure and the following assumptions to determine the grant date fair value of the 2017 and 2016 PSU awards.

Grant Date Assumptions
Assumption	2017 Awards		2016 Awards
Volatility	80.65	%	49.74	%
Risk-free interest rate	1.54	%	1.13	%
Dividend yield for value of awards	—	%	—	%

Reporting Period Assumptions
Assumption	2017 Awards		2016 Awards
Volatility	51.65	%	41.46	%
Risk-free interest rate	2.65	%	2.19	%
Dividend yield for value of awards	—	%	—	%

We used the following weighted average assumptions to estimate the grant date fair value of the stock options granted in the Current Period:

Expected option life – years	6.0
Volatility	63.55	%
Risk-free interest rate	2.72	%
Dividend yield	—	%

Schedule of stock option activity

The following table provides information related to stock option activity in the Current Period: 

	Number of Shares Underlying   Options		Weighted Average Exercise Price Per Share		Weighted   Average Contract Life in Years	Aggregate   Intrinsic Value(a)
	(in thousands)					($ in millions)
Outstanding as of January 1, 2018	16,285		$	8.25	7.73	$	1
Granted	3,611		$	3.01
Exercised	—		$	—		$	—
Expired	(602	)	$	13.83
Forfeited	(1,067	)	$	5.45
Outstanding as of September 30, 2018	18,227		$	7.19	7.44	$	8
Exercisable as of September 30, 2018	8,250		$	10.73	6.05	$	2

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(a) The intrinsic value of a stock option is the amount by which the current market value or the market value upon exercise of the underlying stock exceeds the exercise price of the option.

Restricted stock and stock option compensation

We recognized the following compensation costs related to restricted stock and stock options for the Current Quarter, the Prior Quarter, the Current Period and the Prior Period:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
	($ in millions)
General and administrative expenses	$	6	$	9	$	21	$	20
Oil and natural gas properties	1		3		5		7
Oil, natural gas and NGL production expenses	1		2		4		7
Total restricted stock and stock option compensation	$	8	$	14	$	30	$	34

Assumptions and TSR performance measure to determine grant date fair value of PSUs

We utilized a Monte Carlo simulation for the TSR performance measure and the following assumptions to determine the grant date fair value of the 2017 and 2016 PSU awards.

Grant Date Assumptions
Assumption	2017 Awards		2016 Awards
Volatility	80.65	%	49.74	%
Risk-free interest rate	1.54	%	1.13	%
Dividend yield for value of awards	—	%	—	%

Reporting Period Assumptions
Assumption	2017 Awards		2016 Awards
Volatility	51.65	%	41.46	%
Risk-free interest rate	2.65	%	2.19	%
Dividend yield for value of awards	—	%	—	%

We used the following weighted average assumptions to estimate the grant date fair value of the stock options granted in the Current Period:

Expected option life – years	6.0
Volatility	63.55	%
Risk-free interest rate	2.72	%
Dividend yield	—	%

Schedule of PSU awards

The following table presents a summary of our liability-classified awards:

		Grant Date Fair Value		September 30, 2018
	Units			Fair Value		Vested Liability
		($ in millions)		($ in millions)
2018 PSU Awards:
Payable 2019, 2020 and 2021	3,992,358	$	12	$	18	$	—
2017 PSU Awards:
Payable 2020	1,217,774	$	8	$	6	$	4
2016 PSU Awards:
Payable 2019	2,348,893	$	10	$	11	$	10
2018 CRSU Awards:
Payable 2019, 2020 and 2021	16,034,295	$	48	$	72	$	—

PSU compensation

We recognized the following compensation costs related to restricted stock and stock options for the Current Quarter, the Prior Quarter, the Current Period and the Prior Period:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
	($ in millions)
General and administrative expenses	$	6	$	9	$	21	$	20
Oil and natural gas properties	1		3		5		7
Oil, natural gas and NGL production expenses	1		2		4		7
Total restricted stock and stock option compensation	$	8	$	14	$	30	$	34