CONSOLIDATED BALANCE SHEET (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Cash and cash equivalent	$ 262	$ 247
Receivables net of allowance	908	1,062
Other current assets (Note 5) ($5 and $5 related to Altus VIE)	676	652
Gathering, processing, and transmission facilities ($206 and $203 related to Altus VIE)	670	799
Other property and equipment	1,140	1,140
Accumulated depreciation	34,810	28,987
Equity method interests	1,555	1,258
Deferred charges and other	526	730
Current debt	2	11
Other current liabilities	862	1,149
Long-term debt	8,770	8,555
Asset retirement obligation	1,888	1,811
Other noncurrent liabilities	$ 602	$ 520
Common stock, par value (in USD per share)	$ 0.625	$ 0.625
Common stock, shares authorized (in shares)	860,000,000	860,000,000
Common stock, shares issued (in shares)	418,429,375	417,026,863
Treasury stock, shares (in shares)	40,946,745	40,964,193
Variable Interest Entity, Primary Beneficiary
Cash and cash equivalent	$ 24	$ 6
Receivables net of allowance	95	88
Other current assets (Note 5) ($5 and $5 related to Altus VIE)	5	5
Gathering, processing, and transmission facilities ($206 and $203 related to Altus VIE)	206	203
Other property and equipment	3	4
Accumulated depreciation	13	1
Equity method interests	1,555	1,258
Deferred charges and other	5	4
Current debt	0	10
Other current liabilities	4	21
Long-term debt	624	396
Asset retirement obligation	64	60
Other noncurrent liabilities	$ 144	$ 107