CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Cash Flows From Operating Activities:
Net income (loss)	$ (593)	$ 49	$ (3,020)	$ 781
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion and amortization	70	125	267	352
Amortization of debt issuance costs			6	5
Impairments	361	2	2,495	8
Deferred income taxes	0	11	408	(400)
(Gain) loss on derivatives, unsettled			272	(108)
Stock-based compensation	0	2	2	6
Gain on early extinguishment of debt	0	(7)	(35)	(7)
Loss on sale of assets	0	0	0	3
Other			3	11
Change in assets and liabilities:
Accounts receivable			106	257
Accounts payable			(129)	(124)
Taxes payable			(12)	(3)
Interest payable			3	2
Inventories			3	(2)
Other assets and liabilities			38	(42)
Net cash provided by operating activities			407	739
Cash Flows From Investing Activities:
Capital investments			(700)	(877)
Proceeds from sale of property and equipment			2	42
Net cash used in investing activities			(698)	(835)
Cash Flows From Financing Activities:
Payments on long-term debt			(72)	(43)
Payments on revolving credit facility			(1,449)	0
Borrowings under revolving credit facility			1,415	0
Change in bank drafts outstanding			(9)	(11)
Proceeds from issuance of long-term debt			350	0
Debt issuance costs			(5)	0
Purchase of treasury stock			0	(21)
Proceeds from issuance of common stock, net			152	0
Cash paid for tax withholding			(1)	(1)
Net cash provided by (used in) financing activities			381	(76)
Increase (decrease) in cash and cash equivalents			90	(172)
Cash and cash equivalents at beginning of year			5	201
Cash and cash equivalents at end of period	$ 95	$ 29	$ 95	$ 29