Debt and Interest Expense (Tables)

9 Months Ended

Sep. 30, 2018

Debt Instruments [Abstract]

Debt Outstanding and Debt Activity Tables

The following table presents WES and WGP’s outstanding debt:

	September 30, 2018						December 31, 2017
thousands	Principal		Carrying Value		Fair Value(1)		Principal		Carrying Value		Fair Value (1)
Short-term debt
WGP RCF	$	28,000	$	28,000	$	28,000	$	—	$	—	$	—
WGP long-term debt
WGP RCF	$	—	$	—	$	—	$	28,000	$	28,000	$	28,000
WES long-term debt
2.600% Senior Notes due 2018	—		—		—		350,000		349,684		350,631
5.375% Senior Notes due 2021	500,000		496,669		517,160		500,000		495,815		530,647
4.000% Senior Notes due 2022	670,000		669,020		668,198		670,000		668,849		684,043
3.950% Senior Notes due 2025	500,000		492,596		478,470		500,000		491,885		500,885
4.650% Senior Notes due 2026	500,000		495,592		492,502		500,000		495,245		520,144
4.500% Senior Notes due 2028	400,000		394,514		384,964		—		—		—
4.750% Senior Notes due 2028	400,000		395,806		391,532		—		—		—
5.450% Senior Notes due 2044	600,000		593,319		565,485		600,000		593,234		637,827
5.300% Senior Notes due 2048	700,000		686,601		645,643		—		—		—
5.500% Senior Notes due 2048	350,000		342,347		331,981		—		—		—
WES RCF	—		—		—		370,000		370,000		370,000
Total long-term debt	$	4,620,000	$	4,566,464	$	4,475,935	$	3,518,000	$	3,492,712	$	3,622,177

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

10. DEBT AND INTEREST EXPENSE (CONTINUED)

Debt activity. The following table presents WES and WGP’s debt activity for the nine months ended September 30, 2018:

thousands	Carrying Value
Balance at December 31, 2017	$	3,492,712
WES RCF borrowings	320,000
Issuance of 4.500% Senior Notes due 2028	400,000
Issuance of 5.300% Senior Notes due 2048	700,000
Issuance of 4.750% Senior Notes due 2028	400,000
Issuance of 5.500% Senior Notes due 2048	350,000
Repayment of 2.600% Senior Notes due 2018	(350,000		)
Repayments of WES RCF borrowings	(690,000		)
Other	(28,248		)
Balance at September 30, 2018	$	4,594,464

Interest Expense Table

The following table summarizes the amounts included in interest expense:

	Three Months Ended   September 30,						Nine Months Ended   September 30,
thousands	2018			2017			2018			2017
Third parties
Long-term and short-term debt	$	(53,229	)	$	(36,223	)	$	(143,436	)	$	(106,412	)
Amortization of debt issuance costs and commitment fees	(2,054		)	(2,009		)	(6,955		)	(5,955		)
Capitalized interest	6,967			2,115			17,032			3,991
Total interest expense – third parties	(48,316		)	(36,117		)	(133,359		)	(108,376		)
Affiliates
Deferred purchase price obligation – Anadarko (1)	—			—			—			(71		)
Total interest expense – affiliates	—			—			—			(71		)
Interest expense	$	(48,316	)	$	(36,117	)	$	(133,359	)	$	(108,447	)

⁽¹⁾  See Note 3 for a discussion of the Deferred purchase price obligation - Anadarko.