Debt

12 Months Ended

Dec. 31, 2021

Debt Disclosure [Abstract]

Debt

Debt

Certain debt instruments of the Company's subsidiaries, including those discussed later, contain restrictive and financial covenants and cross-default provisions. In order to borrow under the debt agreements, the subsidiary companies must be in compliance with the applicable covenants and certain other conditions, all of which the subsidiaries, as applicable, were in compliance with at December 31, 2021. In the event the subsidiaries do not comply with the applicable covenants and other conditions, alternative sources of funding may need to be pursued.

The following table summarizes the outstanding revolving credit facilities of the Company's subsidiaries:

Company	Facility	Facility Limit			Amount Outstanding at December 31, 2021		Amount Outstanding at December 31, 2020		Letters of Credit at December 31, 2021			Expiration Date
		(In millions)
Montana-Dakota Utilities Co.	Commercial paper/Revolving credit agreement (a)	$	175.0		$	64.9	$	87.7	$	—		12/19/24
Cascade Natural Gas Corporation	Revolving credit agreement	$	100.0	(b)	$	71.0	$	54.0	$	2.2	(c)	6/7/24
Intermountain Gas Company	Revolving credit agreement	$	85.0	(d)	$	56.5	$	41.9	$	—		6/7/24
Centennial Energy Holdings, Inc.	Commercial paper/Revolving credit agreement (e)	$	600.0		$	385.4	$	37.9	$	—		12/19/24

(a)The commercial paper program is supported by a revolving credit agreement with various banks (provisions allow for increased borrowings, at the option of Montana-Dakota on stated conditions, up to a maximum of $225.0 million). There were no amounts outstanding under the revolving credit agreement.

(b)Certain provisions allow for increased borrowings, up to a maximum of $125.0 million.

(c)(Outstanding letter(s) of credit reduce the amount available under the credit agreement.

(d)(Certain provisions allow for increased borrowings, up to a maximum of $110.0 million.

(e)The commercial paper program is supported by a revolving credit agreement with various banks (provisions allow for increased borrowings, at the option of Centennial on stated conditions, up to a maximum of $700.0 million). There were no amounts outstanding under the revolving credit agreement.

The respective commercial paper programs are supported by revolving credit agreements. While the amount of commercial paper outstanding does not reduce available capacity under the respective revolving credit agreements, Montana-Dakota and Centennial do not issue commercial paper in an aggregate amount exceeding the available capacity under their credit agreements. The commercial paper borrowings may vary during the period, largely the result of fluctuations in working capital requirements due to the seasonality of certain operations of the Company's subsidiaries.

Short-term debt

Montana-Dakota On March 8, 2021, Montana-Dakota entered into a $50.0 million term loan agreement with a LIBOR-based variable interest rate and a maturity date of March 7, 2022. At December 31, 2021, Montana-Dakota had no amount outstanding under the agreement. The agreement contains customary covenants and provisions, including a covenant of Montana-Dakota not to permit, at any time, the ratio of total debt to total capitalization to be greater than 65 percent. The covenants also include certain restrictions on the sale of certain assets, loans and investments.

Long-term debt

Long-term Debt Outstanding Long-term debt outstanding was as follows:

	Weighted Average Interest Rate at December 31, 2021		2021		2020
			(In thousands)
Senior Notes due on dates ranging from October 22, 2022 to September 15, 2061	4.32	%	$	2,125,000	$	1,950,000
Commercial paper supported by revolving credit agreements	.40	%	450,300		125,600
Credit agreements due on June 7, 2024	1.94	%	127,500		95,900
Medium-Term Notes due on dates ranging from September 15, 2027 to March 16, 2029	7.32	%	35,000		35,000
Term Loan Agreement due on September 3, 2032	2.00	%	7,700		8,400
Other notes due on dates ranging from January 2, 2022 to January 1, 2061	1.03	%	2,564		4,034
Less unamortized debt issuance costs			6,090		5,803
Less discount			74		1
Total long-term debt			2,741,900		2,213,130
Less current maturities			148,053		1,555
Net long-term debt			$	2,593,847	$	2,211,575

Montana-Dakota Montana-Dakota's revolving credit agreement supports its commercial paper program. Commercial paper borrowings under this agreement are classified as long-term debt as they are intended to be refinanced on a long-term basis through continued commercial paper borrowings. The credit agreement contains customary covenants and provisions, including covenants of Montana-Dakota not to permit, as of the end of any fiscal quarter, the ratio of funded debt to total capitalization (determined on a consolidated basis) to be greater than 65 percent. Other covenants include limitations on the sale of certain assets and on the making of certain loans and investments.

On September 15, 2021, Montana-Dakota entered into a $125.0 million note purchase agreement with maturity dates ranging from September 15, 2051 to September 15, 2061, at a weighted average interest rate of 3.23 percent. On September 15, 2021 and December 15, 2021, Montana-Dakota issued $75.0 million and $50.0 million, respectively, in senior notes under the note purchase agreement. The agreement contains customary covenants and provisions, including a covenant of Montana-Dakota not to permit, at any time, the ratio of total debt to total capitalization to be greater than 65 percent.

Montana-Dakota's ratio of total debt to total capitalization at December 31, 2021, was 51 percent.

Cascade Any borrowings under the revolving credit agreement are classified as long-term debt as they are intended to be refinanced on a long-term basis through continued borrowings. The credit agreement contains customary covenants and provisions, including a covenant of Cascade not to permit, at any time, the ratio of total debt to total capitalization to be greater than 65 percent. Other covenants include restrictions on the sale of certain assets, limitations on indebtedness and the making of certain investments.

Cascade's ratio of total debt to total capitalization at December 31, 2021, was 51 percent.

Intermountain Any borrowings under the revolving credit agreement are classified as long-term debt as they are intended to be refinanced on a long-term basis through continued borrowings. The credit agreement contains customary covenants and provisions, including a covenant of Intermountain not to permit, at any time, the ratio of total debt to total capitalization to be greater than 65 percent. Other covenants include restrictions on the sale of certain assets, limitations on indebtedness and the making of certain investments.

Intermountain's ratio of total debt to total capitalization at December 31, 2021, was 50 percent.

Centennial Centennial's revolving credit agreement supports its commercial paper program. Commercial paper borrowings under this agreement are classified as long-term debt as they are intended to be refinanced on a long-term basis through continued commercial paper borrowings. Centennial's revolving credit agreement contains customary covenants and provisions, including a covenant of Centennial not to permit, as of the end of any fiscal quarter, the ratio of total consolidated debt to total consolidated capitalization to be greater than 65 percent. Other covenants include restricted payments, restrictions on the sale of certain assets, limitations on subsidiary indebtedness, minimum consolidated net worth, limitations on priority debt and the making of certain loans and investments.

Centennial's ratio of total debt to total capitalization, as defined by its debt covenants, at December 31, 2021, was 43 percent.

Certain of Centennial's financing agreements contain cross-default provisions. These provisions state that if Centennial or any subsidiary of Centennial fails to make any payment with respect to any indebtedness or contingent obligation, in excess of a specified amount, under any agreement that causes such indebtedness to be due prior to its stated maturity or the contingent obligation to become payable, the applicable agreements will be in default.

WBI Energy Transmission WBI Energy Transmission has a $300.0 million uncommitted note purchase and private shelf agreement with an expiration date of May 16, 2022. WBI Energy Transmission had $195.0 million of notes outstanding at December 31, 2021, which reduced the remaining capacity under this uncommitted private shelf agreement to $105.0 million. This agreement contains customary covenants and provisions, including a covenant of WBI Energy Transmission not to permit, as of the end of any fiscal quarter, the ratio of total debt to total capitalization to be greater than 55 percent. Other covenants include a limitation on priority debt and restrictions on the sale of certain assets and the making of certain investments.

On December 23, 2021, WBI Energy Transmission entered into a $50.0 million note purchase agreement with a maturity date of December 23, 2041, at an interest rate of 3.67 percent. The agreement contains customary covenants and provisions, including a covenant of WBI Energy Transmission not to permit, at any time, the ratio of total debt to total capitalization to be greater than 55 percent.

WBI Energy Transmission's ratio of total debt to total capitalization at December 31, 2021, was 38 percent.

Schedule of Debt Maturities Long-term debt maturities, which excludes unamortized debt issuance costs and discount, for the five years and thereafter following December 31, 2021, were as follows:

	2022		2023		2024		2025		2026		Thereafter
	(In thousands)
Long-term debt maturities	$	148,053	$	77,925	$	638,604	$	177,802	$	140,802	$	1,564,878