Consolidated Balance Sheets - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 2,072	$ 1,221
Receivables, less reserve of $4 and $4	779	912
Inventories	306	313
Other current assets	111	144
Total current assets	3,268	2,590
Equity method investments	959	1,003
Property, plant and equipment, less accumulated depreciation, depletion and amortization of $22,763 and $23,260	26,737	27,061
Goodwill	115	115
Other noncurrent assets	1,789	1,542
Total assets	32,868	32,311
Current liabilities:
Accounts payable	1,084	1,313
Payroll and benefits payable	79	133
Accrued taxes	151	132
Other current liabilities	211	150
Long-term debt due within one year	1	1
Total current liabilities	1,526	1,729
Long-term debt	7,280	7,276
Deferred tax liabilities	2,368	2,441
Defined benefit postretirement plan obligations	446	403
Asset retirement obligations	1,614	1,601
Deferred credit and other liabilities	283	308
Total liabilities	$ 13,517	$ 13,758
Commitments and contingencies
Stockholders' Equity
Preferred stock - no shares issued or outstanding (no par value, 26 million shares authorized)	$ 0	$ 0
Common stock issued - 937 million and 770 million shares (par value $1 per share, 1.1 billion shares authorized)	937	770
Common stock, securities exchangeable into common stock - no shares issued or outstanding (no par value, 29 million shares authorized)	0	0
Common stock, held in treasury, at cost - 89 million and 93 million shares	(3,397)	(3,554)
Additional paid-in capital	7,428	6,498
Retained earnings	14,533	14,974
Accumulated other comprehensive loss	(150)	(135)
Total stockholders' equity	19,351	18,553
Total liabilities and stockholders' equity	$ 32,868	$ 32,311