Debt and Other Financing Arrangements (Tables)

12 Months Ended

Dec. 31, 2021

Debt Disclosure [Abstract]

Schedule of Debt and Other Financing Arrangements

	(in thousands)
December 31,	2021		2020
Industrial revenue bonds due from 2022 to 2061*	$	1,350,230	$	1,153,240
Notes, 4.125%, due 2022		600,000		600,000
Notes, 4.000%, due 2023		500,000		500,000
Notes, 2.000%, due 2025		500,000		500,000
Notes, 3.950%, due 2028		500,000		500,000
Notes, 2.700%, due 2030		500,000		500,000
Notes, 6.400%, due 2037		543,331		543,331
Notes, 5.200%, due 2043		338,133		338,133
Notes, 4.400%, due 2048		329,219		329,219
Notes, 2.979%, due 2055		439,312		439,312
Finance lease obligations		179,053		90,338
Total long-term debt and finance lease obligations		5,779,278		5,493,573
Less premium on debt exchange		174,891		180,045
Less debt issuance costs		27,299		30,854
Total amounts outstanding		5,577,088		5,282,674
Less current maturities of long-term debt		601,000		—
Less current portion of finance lease obligations		14,678		10,885
Total long-term debt and finance lease obligations due after    one year	$	4,961,410	$	5,271,789

* The industrial revenue bonds had variable rates ranging from 0.14% to 0.18% at December 31, 2021 and 0.16% to 0.19% at December 31, 2020.