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



	September 30, 2018			December 31, 2017
	(Thousands of dollars)
Commercial paper outstanding, bearing a weighted-average interest rate of 2.85% and 2.23% as of September 30, 2018, and December 31, 2017, respectively.	$	120,000		$	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
$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	30,870			36,607
Total debt	9,023,267			9,198,677
Unamortized portion of terminated swaps	17,179			18,468
Unamortized debt issuance costs and discounts	(87,088		)	(78,193		)
Current maturities of long-term debt	(507,650		)	(432,650		)
Short-term borrowings (a)	(120,000		)	(614,673		)
Long-term debt	$	8,325,708		$	8,091,629

(a) - Individual issuances of commercial paper under our commercial paper program generally mature in 90 days or less. These issuances are supported by and reduce the borrowing capacity under our $2.5 Billion Credit Agreement.