Debt

Debt consisted of the following (in millions):



	September 30, 2018		December 31, 2017
SHORT-TERM DEBT
Commercial paper notes, bearing a weighted-average interest rate of 3.3% ⁽¹⁾	$	60	$	—
Senior secured hedged inventory facility, bearing a weighted-average interest rate of 3.2% and 2.6%, respectively⁽¹⁾	300		664
Other	69		73
Total short-term debt ⁽²⁾	429		737

LONG-TERM DEBT
Senior notes, net of unamortized discounts and debt issuance costs of $61 and $67, respectively	8,939		8,933
Commercial paper notes and senior secured hedged inventory facility borrowings ⁽³⁾	—		247
GO Zone term loans, net of debt issuance costs of $2, bearing a weighted-average interest rate of 2.9%	198		—
Other	3		3
Total long-term debt	9,140		9,183
Total debt ⁽⁴⁾	$	9,569	$	9,920


⁽¹⁾	We classified these commercial paper notes and credit facility borrowings as short-term as of September 30, 2018 and December 31, 2017, as these notes and borrowings were primarily designated as working capital borrowings, were required to be repaid within one year and were primarily for hedged NGL and crude oil inventory and NYMEX and ICE margin deposits.


⁽²⁾	As of September 30, 2018 and December 31, 2017, balance includes borrowings for cash margin deposits with NYMEX and ICE, which are associated with financial derivatives used for hedging purposes.


⁽³⁾	As of December 31, 2017, we classified a portion of our commercial paper notes and credit facility borrowings as long-term based on our ability and intent to refinance such amounts on a long-term basis.

⁽⁴⁾

Our fixed-rate senior notes had a face value of approximately $9.0 billion at both September 30, 2018 and December 31, 2017. We estimated the aggregate fair value of these notes as of September 30, 2018 and December 31, 2017 to be approximately $8.8 billion and $9.1 billion, respectively. Our fixed-rate senior notes are traded among institutions, and these trades are routinely published by a reporting service. Our determination of fair value is based on reported trading activity near the end of the reporting period. We estimate that the carrying value of outstanding borrowings under our credit facilities and commercial paper program approximates fair value as interest rates reflect current market rates. The fair value estimates for our senior notes, credit facilities and commercial paper program are based upon observable market data and are classified in Level 2 of the fair value hierarchy.

Credit Agreements

Go Zone term loans. In August 2018, we entered into an agreement for two $100 million term loans (the “GO Zone term loans”) from the remarketing of our $100,000,000 Mississippi Business Finance Corporation Gulf Opportunity Zone Industrial Development Revenue Bonds (SG Resources Mississippi, LLC Project), Series 2009 and our $100,000,000 Mississippi Business Finance Corporation Gulf Opportunity Zone Industrial Development Revenue Bonds (SG Resources Mississippi, LLC Project), Series 2010 (collectively, the “GO Bonds”). The GO Zone term loans accrue interest in accordance with the interest payable on the related GO Bonds as provided in the GO Bonds Indenture pursuant to which such GO Bonds are issued and governed. The purchasers of the two GO Zone term loans have the right to put, at par, the GO Zone term loans in July 2023. The GO Bonds mature by their terms in May 2032 and August 2035, respectively.

Credit Facilities. In August 2018, we extended the maturity dates of our senior unsecured revolving credit facility and senior secured hedged inventory facility by one year to August 2023 and August 2021, respectively, for each extending lender. Our 364-day senior unsecured revolving credit facility, which had a borrowing capacity of $1.0 billion, matured in August 2018.

Borrowings and Repayments

Total borrowings under our credit facilities and commercial paper program for the nine months ended September 30, 2018 and 2017 were approximately $38.6 billion and $52.6 billion, respectively. Total repayments under our credit facilities and commercial paper program were approximately $39.2 billion and $52.7 billion for the nine months ended September 30, 2018 and 2017, respectively. The variance in total gross borrowings and repayments is impacted by various business and financial factors including, but not limited to, the timing, average term and method of general partnership borrowing activities.

Letters of Credit

In connection with our supply and logistics activities, we provide certain suppliers with irrevocable standby letters of credit to secure our obligation for the purchase and transportation of crude oil, NGL and natural gas. Additionally, we issue letters of credit to support insurance programs, derivative transactions including hedging related margin obligations and construction activities. At September 30, 2018 and December 31, 2017, we had outstanding letters of credit of $181 million and $166 million, respectively.