9. DEBT AND INTEREST EXPENSE

At June 30, 2015, WES’s debt consisted of 5.375% Senior Notes due 2021 (the “2021 Notes”), 4.000% Senior Notes due 2022 (the “2022 Notes”), 2.600% Senior Notes due 2018 (the “2018 Notes”), 5.450% Senior Notes due 2044 (the “2044 Notes”), 3.950% Senior Notes due 2025 (the “2025 Notes”), and borrowings on WES’s senior unsecured revolving credit facility (“WES RCF”).

The following table presents WES and WGP’s outstanding debt as of June 30, 2015, and December 31, 2014:



	June 30, 2015						December 31, 2014
thousands	Principal		Carrying Value		Fair Value ⁽¹⁾		Principal		Carrying Value		Fair Value ⁽¹⁾
WGP working capital facility - Anadarko	$	—	$	—	$	—	$	1,150	$	1,150	$	1,150

Long-term debt
2021 Notes	$	500,000	$	495,995	$	544,930	$	500,000	$	495,714	$	549,530
2022 Notes	670,000		672,752		673,994		670,000		672,930		681,942
2018 Notes	350,000		350,412		352,497		350,000		350,474		352,162
2044 Notes	400,000		393,879		400,692		400,000		393,836		417,619
2025 Notes	500,000		493,985		482,161		—		—		—
WES RCF	270,000		270,000		270,000		510,000		510,000		510,000
Total long-term debt	$	2,690,000	$	2,677,023	$	2,724,274	$	2,430,000	$	2,422,954	$	2,511,253


⁽¹⁾	Fair value is measured using Level 2 inputs.

9. DEBT AND INTEREST EXPENSE (CONTINUED)

Debt activity. The following table presents WES and WGP’s debt activity for the six months ended June 30, 2015:



thousands	Carrying Value
Balance at December 31, 2014	$	2,424,104
WES RCF borrowings	280,000
Issuance of 2025 Notes	500,000
Repayments of WES RCF	(520,000		)
Repayment of WGP working capital facility	(1,150		)
Other	(5,931		)
Balance at June 30, 2015	$	2,677,023

WES Senior Notes. The 2025 Notes issued in June 2015 were offered at a price to the public of 98.789% of the face amount. Including the effects of the issuance and underwriting discounts, the effective interest rate of the 2025 Notes is 4.205%. Interest is paid semi-annually on June 1 and December 1 of each year. Proceeds (net of underwriting discount of $3.3 million, original issue discount and debt issuance costs) were used to repay a portion of the amount outstanding under the WES RCF.

At June 30, 2015, WES was in compliance with all covenants under the indentures governing its outstanding notes.

WES RCF. The interest rate on the WES RCF, which matures in February 2019, was 1.49% and 1.46% at June 30, 2015, and June 30, 2014, respectively. The facility fee rate was 0.20% at June 30, 2015, and June 30, 2014.

As of June 30, 2015, WES had $270.0 million of outstanding borrowings, $12.8 million in outstanding letters of credit and $917.2 million available for borrowing under the WES RCF. At June 30, 2015, WES was in compliance with all covenants under the WES RCF.

WGP working capital facility. On November 1, 2012, WGP entered into a $30.0 million working capital facility (the “WGP WCF”) with Anadarko as the lender. Borrowings under the facility will mature on November 1, 2017. The interest rate was 1.69% and 1.66% at June 30, 2015, and June 30, 2014, respectively.

As of June 30, 2015, WGP had no outstanding borrowings and $30.0 million available for borrowing under the WGP WCF. At June 30, 2015, WGP was in compliance with all covenants under the WGP WCF.

Interest expense. The following table summarizes the amounts included in interest expense:



	Three Months Ended June 30,						Six Months Ended June 30,
thousands	2015			2014			2015			2014
Third parties
Long-term debt	$	24,733		$	21,445		$	48,075		$	37,580
Amortization of debt issuance costs and commitment fees	1,374			1,426			2,666			2,692
Capitalized interest	(2,693		)	(2,007		)	(5,787		)	(5,447		)
Total interest expense – third parties	23,414			20,864			44,954			34,825
Affiliates
WGP WCF	—			—			2			—
Deferred purchase price obligation – Anadarko ⁽¹⁾	4,190			—			5,610			—
Total interest expense – affiliates	4,190			—			5,612			—
Interest expense	$	27,604		$	20,864		$	50,566		$	34,825


⁽¹⁾	See Note 2 for a discussion of the accretion and present value of the Deferred purchase price obligation - Anadarko.