CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Assets
Cash and cash equivalents	$ 38,141	$ 141,646	$ 286,957
Restricted cash	8,373	5,000	0
Accounts and notes receivable
Accounts and notes receivable, gross	492,103	590,986	471,590
Less: Allowance for doubtful accounts	(2,667)	(2,649)	(2,757)
Accounts and notes receivable, net	489,436	588,337	468,833
Inventories
Finished products	340,666	327,711	306,012
Raw materials	29,393	27,152	26,213
Products in process	1,303	1,827	1,314
Operating supplies and other	28,392	27,648	29,860
Inventories	399,754	384,338	363,399
Prepaid expenses	75,495	60,780	38,573
Total current assets	1,011,199	1,180,101	1,157,762
Investments and long-term receivables	35,056	35,115	34,311
Property, plant & equipment
Property, plant & equipment, cost	8,116,439	7,969,312	7,432,388
Allowance for depreciation, depletion & amortization	(4,090,574)	(4,050,381)	(3,980,567)
Property, plant & equipment, net	4,025,865	3,918,931	3,451,821
Goodwill	3,130,161	3,122,321	3,101,241
Other intangible assets, net	1,060,831	1,063,630	829,114
Other noncurrent assets	190,099	184,793	170,075
Total assets	9,453,211	9,504,891	8,744,324
Liabilities
Current maturities of long-term debt	22	41,383	139
Short-term debt	200,000	0	0
Trade payables and accruals	188,163	197,335	175,906
Other current liabilities	195,122	204,154	184,853
Total current liabilities	583,307	442,872	360,898
Long-term debt	2,775,687	2,813,482	2,329,248
Deferred income taxes, net	479,430	464,081	703,491
Deferred revenue	190,731	191,476	196,739
Other noncurrent liabilities	510,846	624,087	633,187
Total liabilities	4,540,001	4,535,998	4,223,563
Other commitments and contingencies (Note 8)
Equity
Common stock, $1 par value, Authorized 480,000 shares, Outstanding 132,290, 132,324 and 132,222 shares, respectively	132,290	132,324	132,222
Capital in excess of par value	2,787,848	2,805,587	2,792,720
Retained earnings	2,138,885	2,180,448	1,734,448
Accumulated other comprehensive loss	(145,813)	(149,466)	(138,629)
Total equity	4,913,210	4,968,893	4,520,761
Total liabilities and equity	$ 9,453,211	$ 9,504,891	$ 8,744,324