Debt and Interest Expense (Tables)

12 Months Ended

Dec. 31, 2015

Debt Instruments [Abstract]

Debt Outstanding and Debt Activity Tables

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

	December 31, 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	$	496,285	$	513,645	$	500,000	$	495,714	$	549,530
2022 Notes	670,000		672,572		595,744		670,000		672,930		681,942
2018 Notes	350,000		350,348		339,293		350,000		350,474		352,162
2044 Notes	400,000		393,923		321,499		400,000		393,836		417,619
2025 Notes	500,000		494,229		422,285		—		—		—
WES RCF	300,000		300,000		300,000		510,000		510,000		510,000
Total long-term debt	$	2,720,000	$	2,707,357	$	2,492,466	$	2,430,000	$	2,422,954	$	2,511,253

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

12.  DEBT AND INTEREST EXPENSE (CONTINUED)

Debt activity. The following table presents WES and WGP’s debt activity for the years ended December 31, 2015 and 2014:

thousands	Carrying Value
Balance at December 31, 2013	$	1,418,169
WES RCF borrowings	1,160,000
Issuance of 2044 Notes	400,000
Issuance of 2018 Notes	100,000
Repayments of WES RCF borrowings	(650,000		)
WGP WCF borrowings	1,150
Other	(5,215		)
Balance at December 31, 2014	$	2,424,104
WES RCF borrowings	400,000
Issuance of 2025 Notes	500,000
Repayments of WES RCF borrowings	(610,000		)
Repayment of WGP WCF borrowings	(1,150		)
Other	(5,597		)
Balance at December 31, 2015	$	2,707,357

Interest Expense Table

The following table summarizes the amounts included in interest expense:

	Year Ended December 31,
thousands	2015			2014			2013
Third parties
Long-term debt	$	102,058		$	81,495		$	59,293
Amortization of debt issuance costs and commitment fees	5,734			5,103			4,449
Capitalized interest	(8,318		)	(9,832		)	(11,945		)
Total interest expense – third parties	99,474			76,766			51,797
Affiliates
WGP WCF	2			3			—
Deferred purchase price obligation – Anadarko (1)	14,398			—			—
Total interest expense – affiliates	14,400			3			—
Interest expense	$	113,874		$	76,769		$	51,797

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