DEBT

The following table sets forth our consolidated debt for the periods indicated:



	December 31, 2018			December 31, 2017
	(Thousands of dollars)
Commercial paper outstanding, bearing a weighted-average interest rate of 2.23% as of December 31, 2017	$	—		$	614,673
Senior unsecured obligations:
$425,000 at 3.2% due September 2018	—			425,000
$1,000,000 term loan, rate of 2.87% as of December 31, 2017, due January 2019	—			500,000
$500,000 at 8.625% due March 2019	500,000			500,000
$300,000 at 3.8% due March 2020	300,000			300,000
$1,500,000 term loan, rate of 3.63% as of December 31, 2018, due November 2021	550,000			—
$700,000 at 4.25% due February 2022	547,397			547,397
$900,000 at 3.375 % due October 2022	900,000			900,000
$425,000 at 5.0 % due September 2023	425,000			425,000
$500,000 at 7.5% due September 2023	500,000			500,000
$500,000 at 4.9 % due March 2025	500,000			500,000
$500,000 at 4.0% due July 2027	500,000			500,000
$800,000 at 4.55% due July 2028	800,000			—
$100,000 at 6.875% due September 2028	100,000			100,000
$400,000 at 6.0% due June 2035	400,000			400,000
$600,000 at 6.65% due October 2036	600,000			600,000
$600,000 at 6.85% due October 2037	600,000			600,000
$650,000 at 6.125% due February 2041	650,000			650,000
$400,000 at 6.2% due September 2043	400,000			400,000
$700,000 at 4.95% due July 2047	700,000			700,000
$450,000 at 5.2% due July 2048	450,000			—
Guardian Pipeline
Weighted average 7.85% due December 2022	28,957			36,607
Total debt	9,451,354			9,198,677
Unamortized portion of terminated swaps	16,750			18,468
Unamortized debt issuance costs and discounts	(87,120		)	(78,193		)
Current maturities of long-term debt	(507,650		)	(432,650		)
Short-term borrowings (a)	—			(614,673		)
Long-term debt	$	8,873,334		$	8,091,629

(a) - Individual issuances of commercial paper under our commercial paper program generally mature in 90 days or less.

$2.5 Billion Credit Agreement - In June 2018, we extended the term of our $2.5 Billion Credit Agreement by one year to June 2023. Our $2.5 Billion Credit Agreement is a revolving credit facility and contains certain financial, operational and legal covenants. Among other things, these covenants include maintaining a ratio of indebtedness to adjusted EBITDA (EBITDA, as defined in our $2.5 Billion Credit Agreement, adjusted for all noncash charges and increased for projected EBITDA from certain lender-approved capital expansion projects). At December 31, 2018, due to our acquisition of the remaining 20 percent interest in WTLPG for $195 million, the covenant increased to 5.5 to 1 for the second half of 2018 and first quarter 2019, and 5.0 to 1 thereafter.

Our $2.5 Billion Credit Agreement includes a $100 million sublimit for the issuance of standby letters of credit and a $200 million sublimit for swingline loans. Under the terms of our $2.5 Billion Credit Agreement, we may request an increase in the size of the facility to an aggregate of $3.5 billion by either commitments from new lenders or increased commitments from existing lenders. Our $2.5 Billion Credit Agreement contains provisions for an applicable margin rate and an annual facility fee, both of which adjust with changes in our credit ratings. Based on our current credit ratings, borrowings, if any, will accrue at LIBOR plus 110 basis points, and the annual facility fee is 15 basis points. We have the option to request an additional one-year extension, subject to lender approval, which may be used for working capital, capital expenditures, acquisitions and mergers, the issuance of letters of credit and for other general corporate purposes. At December 31, 2018, our ratio of indebtedness to adjusted EBITDA was 3.5 to 1, and we were in compliance with all covenants under our $2.5 Billion Credit Agreement.

At December 31, 2018 and 2017, we had letters of credit issued totaling $1.4 million and $15.8 million, respectively, and no borrowings outstanding under our $2.5 Billion Credit Agreement.

Senior Unsecured Obligations - All notes are senior unsecured obligations, ranking equally in right of payment with all of our existing and future unsecured senior indebtedness, and are structurally subordinate to any of the existing and future debt and other liabilities of any nonguarantor subsidiaries.

Issuances - In November 2018, we entered into our $1.5 Billion Term Loan Agreement with a syndicate of banks, which is available to be drawn until May 2019. Our $1.5 Billion Term Loan Agreement matures in November 2021 and bears interest at LIBOR plus 112.5 basis points based on our current credit ratings. The agreement contains an option, which may be exercised up to two times, to extend the term of the loan, in each case, for an additional one-year term subject to approval of the banks. Our $1.5 Billion Term Loan Agreement allows prepayment of all or any portion outstanding, without penalty or premium, and contains substantially the same covenants as those contained in our $2.5 Billion Credit Agreement. As of December 31, 2018, we had borrowings totaling $550 million outstanding under our $1.5 Billion Term Loan Agreement, which were used for general corporate purposes, including repayment of existing indebtedness.

In July 2018, we completed an underwritten public offering of $1.25 billion senior unsecured notes consisting of $800 million, 4.55 percent senior notes due 2028 and $450 million, 5.2 percent senior notes due 2048. The net proceeds, after deducting underwriting discounts, commissions and offering expenses, were $1.23 billion. The proceeds were used for general corporate purposes, which included repayment of existing indebtedness and funding capital expenditures.

In July 2017, we completed an underwritten public offering of $1.2 billion senior unsecured notes consisting of $500 million, 4.0 percent senior notes due 2027, and $700 million, 4.95 percent senior notes due 2047. The net proceeds, after deducting underwriting discounts, commissions and offering expenses, were $1.2 billion. The proceeds were used for general corporate purposes, which included repayment of existing indebtedness and capital expenditures.

In 2016, ONEOK Partners entered into the $1.0 billion senior unsecured ONEOK Partners Term Loan Agreement with a syndicate of banks that was due to mature in 2019 with interest at LIBOR plus 130 basis points based on our current credit ratings and contained substantially the same covenants as our $2.5 Billion Credit Agreement. As of January 2018, all amounts outstanding under the ONEOK Partners Term Loan Agreement had been repaid. See “Repayments” section below.

Repayments - In August 2018, we repaid the $425 million, 3.2 percent senior notes due September 2018 with cash on hand.

We repaid the ONEOK Partners Term Loan Agreement due 2019 with two payments of $500 million each in January 2018 and July 2017 with a combination of cash on hand and short-term borrowings.

In September 2017, we repaid ONEOK Partners’ $400 million, 2.0 percent senior notes due in October 2017 with a combination of cash on hand and short-term borrowings.

In July 2017, we redeemed our 6.5 percent senior notes due 2028 at a redemption price of $87.0 million, including the outstanding principal amount, plus accrued and unpaid interest, with cash on hand.

In October 2016, ONEOK Partners repaid its $450 million, 6.15 percent senior notes at maturity with a combination of cash on hand and short-term borrowings.

The aggregate maturities of long-term debt outstanding as of December 31, 2018, for the years 2019 through 2023 are shown below:



	Senior Notes		Guardian Pipeline		Total

2019	$	500.0	$	7.7	$	507.7
2020	$	300.0	$	7.7	$	307.7
2021	$	550.0	$	7.7	$	557.7
2022	$	1,447.4	$	5.9	$	1,453.3
2023	$	925.0	$	—	$	925.0

Covenants - Our senior notes are governed by indentures containing covenants, including among other provisions, limitations on our ability to place liens on our property or assets and to sell and leaseback our property. The indentures governing our 6.875 percent senior notes due 2028 include an event of default upon acceleration of other indebtedness of $15 million or more, and the indentures governing the remainder of our senior notes include an event of default upon the acceleration of other indebtedness of $100 million or more. Such events of default would entitle the trustee or the holders of 25 percent in aggregate principal amount of the outstanding senior notes to declare those senior notes immediately due and payable in full. The indenture for the 7.5 percent notes due 2023 also contains a provision that allows the holders of the notes to require ONEOK to offer to repurchase all or any part of their notes if a change of control and a credit rating downgrade occur at a purchase price of 101 percent of the principal amount, plus accrued and unpaid interest, if any.

We may redeem our senior notes, in whole or in part, at any time prior to their maturity at a redemption price equal to the principal amount, plus accrued and unpaid interest and a make-whole premium. We may redeem the balance of our senior notes due 2020, 2022, 2023, 2025, 2027, 2028 (4.55%), 2041, 2043, 2047 and 2048 at a redemption price equal to the principal amount, plus accrued and unpaid interest, starting one to six months before the maturity date as stipulated in the respective contract terms. Our senior notes are senior unsecured obligations, ranking equally in right of payment with all of our existing and future unsecured senior indebtedness.

Guardian Pipeline Senior Notes - These senior notes were issued under a master shelf agreement dated November 8, 2001, with certain financial institutions. Principal payments are due quarterly through 2022. Guardian Pipeline’s senior notes contain financial covenants that require the maintenance of certain financial ratios as defined in the master shelf agreement based on Guardian Pipeline’s financial position and results of operations. Upon any breach of these covenants, all amounts outstanding under the master shelf agreement may become due and payable immediately. At December 31, 2018, Guardian Pipeline was in compliance with its financial covenants.

Other - We amortize premiums, discounts and expenses incurred in connection with the issuance of long-term debt consistent with the terms of the respective debt instrument.

Debt Guarantees - ONEOK, ONEOK Partners and the Intermediate Partnership have cross guarantees in place for our and ONEOK Partners’ indebtedness.