DEBT (Tables)

12 Months Ended

Dec. 31, 2018

Long-term Debt, Unclassified [Abstract]

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.

Aggregate maturities of long-term debt outstanding

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