CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020
Assets
Cash and cash equivalents	$ 722,344	$ 1,197,068	$ 120,041
Restricted cash	168,595	945	232
Accounts and notes receivable
Accounts and notes receivable, gross	596,006	558,848	601,182
Allowance for doubtful accounts	(2,878)	(2,551)	(3,517)
Accounts and notes receivable, net	593,128	556,297	597,665
Inventories [Abstract]
Finished products	368,758	378,389	403,612
Raw materials	36,095	33,780	33,676
Products in process	4,573	4,555	5,010
Operating supplies and other	31,903	31,861	28,449
Inventories	441,329	448,585	470,747
Other current assets	67,612	74,270	88,095
Total current assets	1,993,008	2,277,165	1,276,780
Investments and long-term receivables	34,265	34,301	57,987
Property, plant & equipment [Abstract]
Property, plant & equipment, cost	9,110,336	9,102,086	8,907,788
Allowances for depreciation, depletion & amortization	(4,746,996)	(4,676,087)	(4,506,700)
Property, plant & equipment, net	4,363,340	4,425,999	4,401,088
Operating lease right-of-use assets, net	421,625	423,128	420,930
Goodwill	3,172,112	3,172,112	3,167,061
Other intangible assets, net	1,114,617	1,123,544	1,083,515
Other noncurrent assets	233,793	230,656	222,021
Total assets	11,332,760	11,686,905	10,629,382
Liabilities
Current maturities of long-term debt	15,436	515,435	25
Trade payables and accruals	255,624	273,080	243,019
Other current liabilities	294,797	259,368	232,632
Total current liabilities	565,857	1,047,883	475,676
Long-term debt	2,772,901	2,772,240	2,785,566
Deferred income taxes, net	733,561	706,050	648,405
Deferred revenue	172,377	174,045	178,568
Operating lease liabilities	397,306	399,582	399,489
Other noncurrent liabilities	554,517	559,775	551,352
Total liabilities	5,196,519	5,659,575	5,039,056
Other commitments and contingencies (Note 8)
Equity
Common stock, $1 par value, Authorized 480,000 shares, Outstanding 132,664, 132,516 and 132,433 shares, respectively	132,664	132,516	132,433
Capital in excess of par value	2,797,687	2,802,012	2,782,738
Retained earnings	3,385,604	3,274,107	2,885,084
Accumulated other comprehensive loss	(179,714)	(181,305)	(209,929)
Total equity	6,136,241	6,027,330	5,590,326
Total liabilities and equity	$ 11,332,760	$ 11,686,905	$ 10,629,382