Debt and Financing Arrangements (Tables)

12 Months Ended

Dec. 31, 2021

Debt Disclosure [Abstract]

Long-term debt

	December 31,
	2021		2020
	(Thousands)
Debentures:
7.08% due 2026	$	7,500	$	7,500
7.25% due 2026	200,000		200,000
Total debentures	207,500		207,500
Notes:
7.85% due 2026	1,000,000		1,000,000
4.0% due 2028	400,000		400,000
3.25% due 2030	700,000		700,000
5.4% due 2041	375,000		375,000
4.45% due 2042	400,000		400,000
4.6% due 2048	600,000		600,000
3.95% due 2050	500,000		500,000
Total notes	3,975,000		3,975,000
Other financing obligations	1,156,124		1,104,143
Total long-term debt, including current portion	5,338,624		5,286,643
Unamortized debt issuance costs	(30,393)		(32,505)
Unamortized debt premium and discount, net	(13,613)		(14,358)
Long-term debt due within one year	(25,594)		(22,640)
Total long-term debt	$	5,269,024	$	5,217,140

Maturities of long-term debt

The following table presents aggregate minimum maturities of long-term debt and other financing obligations outstanding at December 31, 2021, excluding net unamortized debt premium (discount) and debt issuance costs, for each of the next five years (in thousands): 

2022	$	25,594
2023	$	28,029
2024	$	30,701
2025	$	33,630
2026	$	1,244,343