CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Cash Flows From Operating Activities:
Net income (loss)	$ (880)	$ 138	$ (2,427)	$ 732
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion and amortization	84	115	197	227
Amortization of debt issuance costs			4	2
Impairments	655	6	2,134	6
Deferred income taxes	0	15	408	(411)
Gain on derivatives, unsettled			(17)	(96)
Stock-based compensation	1	2	2	4
Gain on early extinguishment of debt	(7)	0	(35)	0
Loss on sale of assets	0	3	0	3
Other			0	10
Change in assets and liabilities:
Accounts receivable			94	221
Accounts payable			(121)	(129)
Taxes payable			(11)	(6)
Interest payable			(1)	1
Inventories			6	4
Other assets and liabilities			21	(25)
Net cash provided by operating activities			254	543
Cash Flows From Investing Activities:
Capital investments			(472)	(586)
Proceeds from sale of property and equipment			2	26
Net cash used in investing activities			(470)	(560)
Cash Flows From Financing Activities:
Payments on long-term debt			(72)	0
Payments on revolving credit facility			(919)	0
Borrowings under revolving credit facility			1,221	0
Change in bank drafts outstanding			(8)	(7)
Purchase of treasury stock			0	(21)
Cash paid for tax withholding			(1)	(1)
Net cash provided by (used in) financing activities			221	(29)
Increase (decrease) in cash and cash equivalents			5	(46)
Cash and cash equivalents at beginning of year			5	201
Cash and cash equivalents at end of period	$ 10	$ 155	$ 10	$ 155