Debt

Debt consisted of the following (in millions):



	June 30, 2017		December 31, 2016
SHORT-TERM DEBT
Commercial paper notes, bearing a weighted-average interest rate of 2.0% and 1.6%, respectively⁽¹⁾	$	677	$	563
Senior secured hedged inventory facility, bearing a weighted-average interest rate of 2.3% and 1.8%, respectively⁽¹⁾	300		750
Senior notes:
6.13% senior notes due January 2017	—		400
Other	137		2
Total short-term debt ⁽²⁾	1,114		1,715

LONG-TERM DEBT
Senior notes, net of unamortized discounts and debt issuance costs of $72 and $76, respectively ⁽³⁾	9,878		9,874
Commercial paper notes, bearing a weighted-average interest rate of 2.0% and 1.6%, respectively ⁽³⁾	159		247
Other	3		3
Total long-term debt	10,040		10,124
Total debt ⁽⁴⁾	$	11,154	$	11,839


⁽¹⁾	We classified these commercial paper notes and credit facility borrowings as short-term as of June 30, 2017 and December 31, 2016, 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 June 30, 2017 and December 31, 2016, balance includes borrowings of $12 million and $410 million, respectively, for cash margin deposits with NYMEX and ICE, which are associated with financial derivatives used for hedging purposes.


⁽³⁾	As of June 30, 2017, we have classified our $600 million, 6.50% senior notes due May 2018 as long-term and as of June 30, 2017 and December 31, 2016, we have classified a portion of our commercial paper notes as long-term based on our ability and intent to refinance such amounts on a long-term basis.

⁽⁴⁾

Our fixed-rate senior notes (including current maturities) had a face value of approximately $9.9 billion and $10.3 billion as of June 30, 2017 and December 31, 2016, respectively. We estimated the aggregate fair value of these notes as of June 30, 2017 and December 31, 2016 to be approximately $10.1 billion and $10.4 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.

Borrowings and Repayments

Total borrowings under our credit facilities and commercial paper program for the six months ended June 30, 2017 and 2016 were approximately $36.8 billion and $23.0 billion, respectively. Total repayments under our credit facilities and commercial paper program were approximately $37.2 billion and $23.6 billion for the six months ended June 30, 2017 and 2016, 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 of crude oil, NGL and natural gas. Additionally, we issue letters of credit to support insurance programs, derivative transactions and construction activities. At June 30, 2017 and December 31, 2016, we had outstanding letters of credit of $105 million and $73 million, respectively.

Senior Notes Repayments

Our $400 million, 6.13% senior notes were repaid in January 2017. We utilized cash on hand and available capacity under our commercial paper program and credit facilities to repay these notes.