9. DEBT AND INTEREST EXPENSE

At September 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 September 30, 2017, and December 31, 2016:



	September 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		495,541		536,712		500,000		494,734		536,252
2022 Notes	670,000		668,795		693,789		670,000		668,634		681,723
2018 Notes	350,000		349,558		351,770		350,000		349,188		351,531
2044 Notes	600,000		593,206		634,283		600,000		593,132		615,753
2025 Notes	500,000		491,653		503,322		500,000		490,971		492,499
2026 Notes	500,000		495,133		525,069		500,000		494,802		518,441
WES RCF	250,000		250,000		250,000		—		—		—
Total long-term debt	$	3,398,000	$	3,371,886	$	3,522,945	$	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 nine months ended September 30, 2017:



thousands	Carrying Value
Balance at December 31, 2016	$	3,119,461
WES RCF borrowings	250,000
Other	2,425
Balance at September 30, 2017	$	3,371,886

WGP RCF. As of September 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 September 30, 2017 and 2016, the interest rate on the outstanding WGP RCF borrowings was 3.24% and 2.53%, respectively. The commitment fee rate was 0.30% at September 30, 2017 and 2016. At September 30, 2017, WGP was in compliance with all covenants under the WGP RCF.

WGP WCF. As of September 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 was 2.74% and 2.03% at September 30, 2017 and 2016, respectively. At September 30, 2017, WGP was in compliance with all covenants under the WGP WCF. The WGP WCF will mature on November 1, 2017, and WGP does not intend to renew this facility.

WES Senior Notes. The 2018 Notes, which are due in August 2018, were classified as long-term debt on the consolidated balance sheet at September 30, 2017, as WES has the ability and intent to refinance these obligations using long-term debt. At September 30, 2017, WES was in compliance with all covenants under the indentures governing its outstanding notes.

9. DEBT AND INTEREST EXPENSE (CONTINUED)

WES RCF. As of September 30, 2017, WES had $250.0 million of outstanding WES RCF borrowings and $4.6 million in outstanding letters of credit, resulting in $945.4 million available for borrowing under the WES RCF, which matures in February 2020. As of September 30, 2017 and 2016, the interest rate on the outstanding WES RCF borrowings was 2.54% and 1.82%, respectively. The facility fee rate was 0.20% at September 30, 2017 and 2016. At September 30, 2017, WES was in compliance with all covenants under the WES RCF.

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



	Three Months Ended September 30,						Nine Months Ended September 30,
thousands	2017			2016			2017			2016
Third parties
Long-term debt	$	(36,223	)	$	(31,795	)	$	(106,412	)	$	(88,123	)
Amortization of debt issuance costs and commitment fees	(2,009		)	(2,022		)	(5,955		)	(5,517		)
Capitalized interest	2,115			1,343			3,991			4,674
Total interest expense – third parties	(36,117		)	(32,474		)	(108,376		)	(88,966		)
Affiliates
Deferred purchase price obligation – Anadarko ⁽¹⁾	—			1,173			(71		)	12,097
Total interest expense – affiliates	—			1,173			(71		)	12,097
Interest expense	$	(36,117	)	$	(31,301	)	$	(108,447	)	$	(76,869	)


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