CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018		Dec. 31, 2017
Cash Flows From Operating Activities:
Net income	$ 891	$ 537	[1]	$ 1,046	[1]
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	471	560		504
Amortization of debt issuance costs	8	8		9
Impairments	16	171		0
Deferred income taxes	(409)	0		(71)
(Gain) loss on derivatives, unsettled	(94)	24		(451)
Stock-based compensation	8	14		24
Gain (Loss) on Extinguishment of Debt	(8)	17		70
(Gain) loss on sale of operating assets, net	2	(17)		(6)
Other	10	(1)		13
Change in assets and liabilities:
Accounts receivable	234	(153)		(65)
Accounts payable	(141)	65		48
Taxes payable	0	2		4
Interest payable	0	(10)		(2)
Inventories	(7)	(13)		(1)
Other assets and liabilities	(17)	19		(25)
Net cash provided by operating activities	964	1,223		1,097
Cash Flows From Investing Activities:
Capital investments	(1,099)	(1,290)		(1,268)
Proceeds from sale of property and equipment	54	1,643		10
Other	0	6		6
Net cash provided by (used in) investing activities	(1,045)	359		(1,252)
Cash Flows From Financing Activities:
Payments on current portion of long-term debt	(52)	0		(328)
Payments on long-term debt	(54)	(2,095)		(1,139)
Payments on revolving credit facility	(532)	(1,983)		0
Borrowings under revolving credit facility	566	1,983		0
Change in bank drafts outstanding	(19)	17		9
Proceeds from issuance of long-term debt	0	0		1,150
Debt issuance costs	(3)	(9)		(24)
Purchase of treasury stock	(21)	(180)		0
Preferred stock dividend	0	(27)		(16)
Cash paid for tax withholding	(1)	(3)		(2)
Other	1	0		(2)
Net cash used in financing activities	(115)	(2,297)		(352)
Decrease in cash and cash equivalents	(196)	(715)		(507)
Cash and cash equivalents at beginning of year	201	916		1,423
Cash and cash equivalents at end of year	$ 5	$ 201		$ 916

[1] In 2018 and 2017, deferred tax activity incurred in other comprehensive income was offset by a valuation allowance.