9. DEBT AND INTEREST EXPENSE

At June 30, 2017, WGP’s debt consisted of borrowings under the WGP RCF and WES’s 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”), 4.650% Senior Notes due 2026 (the “2026 Notes”) and borrowings on the WES RCF.

The following table presents WES and WGP’s outstanding debt as of June 30, 2017, and December 31, 2016:



	June 30, 2017						December 31, 2016
thousands	Principal		Carrying Value		Fair Value ⁽¹⁾		Principal		Carrying Value		Fair Value ⁽¹⁾
WGP RCF	$	28,000	$	28,000	$	28,000	$	28,000	$	28,000	$	28,000
2021 Notes	500,000		495,268		537,476		500,000		494,734		536,252
2022 Notes	670,000		668,740		686,001		670,000		668,634		681,723
2018 Notes	350,000		349,434		351,057		350,000		349,188		351,531
2044 Notes	600,000		593,179		618,294		600,000		593,132		615,753
2025 Notes	500,000		491,423		497,615		500,000		490,971		492,499
2026 Notes	500,000		495,021		517,289		500,000		494,802		518,441
WES RCF	160,000		160,000		160,000		—		—		—
Total long-term debt	$	3,308,000	$	3,281,065	$	3,395,732	$	3,148,000	$	3,119,461	$	3,224,199


⁽¹⁾	Fair value is measured using the market approach and Level 2 inputs.

Debt activity. The following table presents WES and WGP’s debt activity for the six months ended June 30, 2017:



thousands	Carrying Value
Balance at December 31, 2016	$	3,119,461
WES RCF borrowings	160,000
Other	1,604
Balance at June 30, 2017	$	3,281,065

WGP RCF. As of June 30, 2017, WGP had $28.0 million of outstanding borrowings and $222.0 million available for borrowing under the WGP RCF, which matures in March 2019. As of June 30, 2017 and 2016, the interest rate on the outstanding WGP RCF borrowings was 3.23% and 2.72%, respectively. The commitment fee rate was 0.30% and 0.35% at June 30, 2017 and 2016, respectively. At June 30, 2017, WGP was in compliance with all covenants under the WGP RCF.

WGP WCF. As of June 30, 2017, WGP had no outstanding borrowings and $30.0 million available for borrowing under the WGP WCF. The interest rate on the WGP WCF, which matures in November 2017, was 2.73% and 1.97% at June 30, 2017 and 2016, respectively. At June 30, 2017, WGP was in compliance with all covenants under the WGP WCF.

WES Senior Notes. At June 30, 2017, WES was in compliance with all covenants under the indentures governing its outstanding notes.

WES RCF. As of June 30, 2017, WES had $160.0 million of outstanding WES RCF borrowings and $4.9 million in outstanding letters of credit, resulting in $1.035 billion available for borrowing under the WES RCF, which matures in February 2020. As of June 30, 2017 and 2016, the interest rate on the outstanding WES RCF borrowings was 2.53% and 1.77%, respectively. The facility fee rate was 0.20% at June 30, 2017 and 2016. At June 30, 2017, WES was in compliance with all covenants under the WES RCF.

9. DEBT AND INTEREST EXPENSE (CONTINUED)

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



	Three Months Ended June 30,						Six Months Ended June 30,
thousands	2017			2016			2017			2016
Third parties
Long-term debt	$	(35,375	)	$	(28,472	)	$	(70,189	)	$	(56,328	)
Amortization of debt issuance costs and commitment fees	(1,982		)	(1,900		)	(3,946		)	(3,495		)
Capitalized interest	1,060			1,482			1,876			3,331
Total interest expense – third parties	(36,297		)	(28,890		)	(72,259		)	(56,492		)
Affiliates
Deferred purchase price obligation – Anadarko ⁽¹⁾	—			15,461			(71		)	10,924
Total interest expense – affiliates	—			15,461			(71		)	10,924
Interest expense	$	(36,297	)	$	(13,429	)	$	(72,330	)	$	(45,568	)


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