Derivative and Hedging Activities (Tables)

3 Months Ended

Mar. 31, 2018

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of estimated fair values of oil, natural gas and NGL derivative instruments

The estimated fair values of our oil, natural gas and NGL derivative instrument assets (liabilities) as of March 31, 2018 and December 31, 2017 are provided below: 

	March 31, 2018				December 31, 2017
	Notional Volume	Fair Value			Notional Volume	Fair Value
		($ in millions)				($ in millions)
Oil (mmbbl):
Fixed-price swaps	24	$	(180	)	21	$	(151	)
Three-way collars	1	(12		)	2	(10		)
Call swaptions	2	(19		)	2	(13		)
Basis protection swaps	7	5			11	(9		)
Total oil	34	(206		)	36	(183		)
Natural gas (bcf):
Fixed-price swaps	358	44			532	149
Three-way collars	88	—			—	—
Collars	36	8			47	11
Call options	93	(1		)	110	(3		)
Basis protection swaps	41	3			65	(7		)
Total natural gas	616	54			754	150
NGL (mmgal):
Fixed-price swaps	47	—			33	(2		)
Total estimated fair value		$	(152	)		$	(35	)

Schedule of effect of derivative instruments, condensed consolidated balance sheets

The following table presents the fair value and location of each classification of derivative instrument included in the condensed consolidated balance sheets as of March 31, 2018 and December 31, 2017 on a gross basis and after same-counterparty netting:

Balance Sheet Classification	Gross Fair Value			Amounts Netted in the Consolidated Balance Sheets			Net Fair Value Presented in the Consolidated Balance Sheet
	($ in millions)
As of March 31, 2018
Commodity Contracts:
Short-term derivative asset	$	60		$	(57	)	$	3
Long-term derivative asset	5			(5		)	—
Short-term derivative liability	(206		)	57			(149		)
Long-term derivative liability	(11		)	5			(6		)
Total derivatives	$	(152	)	$	—		$	(152	)
As of December 31, 2017
Commodity Contracts:
Short-term derivative asset	$	157		$	(130	)	$	27
Short-term derivative liability	(188		)	130			(58		)
Long-term derivative liability	(4		)	—			(4		)
Total derivatives	$	(35	)	$	—		$	(35	)

Schedule of effect of derivative instruments, condensed consolidated statements of operations

The components of oil, natural gas and NGL revenues for the Current Quarter and the Prior Quarter are presented below:

	Three Months Ended March 31,
	2018			2017
	($ in millions)
Oil, natural gas and NGL revenues	$	1,360		$	1,147
Gains (losses) on undesignated oil, natural gas and NGL derivatives	(107		)	332
Losses on terminated cash flow hedges	(10		)	(10		)
Total oil, natural gas and NGL revenues	$	1,243		$	1,469

Schedule of effect of derivative instruments, accumulated other comprehensive income (loss)

A reconciliation of the changes in accumulated other comprehensive income (loss) in our consolidated statements of stockholders’ equity related to our cash flow hedges is presented below:

	Three Months Ended March 31,
	2018						2017
	Before  Tax			After  Tax			Before  Tax			After  Tax
	($ in millions)
Balance, beginning of period	$	(114	)	$	(57	)	$	(153	)	$	(96	)
Net change in fair value	—			—			4			4
Losses reclassified to income	10			10			10			10
Balance, end of period	$	(104	)	$	(47	)	$	(139	)	$	(82	)

Schedule of financial assets (liabilities)

The following table provides information for financial assets (liabilities) measured at fair value on a recurring basis as of March 31, 2018 and December 31, 2017:

	Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)			Total Fair Value
			($ in millions)
As of March 31, 2018
Derivative Assets (Liabilities):
Commodity assets	$	—	$	53		$	12		$	65
Commodity liabilities	—		(181		)	(36		)	(217		)
Total derivatives	$	—	$	(128	)	$	(24	)	$	(152	)
As of December 31, 2017
Derivative Assets (Liabilities):
Commodity assets	$	—	$	—		$	8		$	8
Commodity liabilities	—		(20		)	(23		)	(43		)
Total derivatives	$	—	$	(20	)	$	(15	)	$	(35	)

A summary of the changes in the fair values of our financial assets (liabilities) classified as Level 3 during the Current Quarter and the Prior Quarter is presented below:

	Commodity Derivatives
	($ in millions)
Balance, as of January 1, 2018	$	(15	)
Total gains (losses) (realized/unrealized):
Included in earnings(a)	(8		)
Total purchases, issuances, sales and settlements:
Settlements	(1		)
Balance, as of March 31, 2018	$	(24	)
Balance, as of January 1, 2017	$	(10	)
Total gains (losses) (realized/unrealized):
Included in earnings(a)	12
Total purchases, issuances, sales and settlements:
Settlements	1
Balance, as of March 31, 2017	$	3

___________________________________________

(a)		Commodity Derivatives
		2018			2017
		($ in millions)
	Total gains (losses) included in earnings for the period	$	(8	)	$	12
	Change in unrealized gains (losses) related to assets still held at reporting date	$	(10	)	$	5

The following table provides fair value measurement information for the above-noted financial assets (liabilities) measured at fair value on a recurring basis as of March 31, 2018 and December 31, 2017:

	Quoted Prices in Active Markets (Level 1)			Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Fair Value
	($ in millions)
As of March 31, 2018
Financial Assets (Liabilities):
Other current assets	$	52		$	—	$	—	$	52
Other current liabilities	(52		)	—		—		(52		)
Total	$	—		$	—	$	—	$	—
As of December 31, 2017
Financial Assets (Liabilities):
Other current assets	$	57		$	—	$	—	$	57
Other current liabilities	(60		)	—		—		(60		)
Total	$	(3	)	$	—	$	—	$	(3	)

Schedule of quantitative information about level 3 inputs used

The following table presents quantitative information about Level 3 inputs used in the fair value measurement of our commodity derivative contracts at fair value as of March 31, 2018:

Instrument Type	Unobservable Input	Range	Weighted Average	Fair Value March 31, 2018
				($ in millions)
Oil trades	Oil price volatility curves	19.20% – 30.57%	27.29%	$	(31	)
Natural gas trades	Natural gas price volatility curves	14.74% – 40.22%	20.73%	$	7