XML 93 R71.htm IDEA: XBRL DOCUMENT v3.8.0.1
Debt and Interest Expense - Debt Outstanding Table (Details) - USD ($)
Dec. 31, 2017
Dec. 31, 2016
Oct. 31, 2016
Debt Instrument [Line Items]      
Total long-term debt principal $ 3,518,000,000 $ 3,148,000,000  
Carrying value 3,492,712,000 3,119,461,000  
Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]      
Debt Instrument [Line Items]      
Fair value [1] 3,622,177,000 3,224,199,000  
WGP RCF [Member] | Revolving Credit Facility [Member]      
Debt Instrument [Line Items]      
Principal 28,000,000 28,000,000  
Carrying value 28,000,000 28,000,000  
WGP RCF [Member] | Revolving Credit Facility [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]      
Debt Instrument [Line Items]      
Fair value [1] 28,000,000 28,000,000  
Western Gas Partners, LP [Member] | WES RCF [Member] | Revolving Credit Facility [Member]      
Debt Instrument [Line Items]      
Principal 370,000,000 0  
Carrying value 370,000,000 0  
Western Gas Partners, LP [Member] | WES RCF [Member] | Revolving Credit Facility [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]      
Debt Instrument [Line Items]      
Fair value [1] 370,000,000 0  
Western Gas Partners, LP [Member] | Senior Notes [Member] | 5.375% Senior Notes due 2021 [Member]      
Debt Instrument [Line Items]      
Principal 500,000,000 500,000,000  
Carrying value 495,815,000 494,734,000  
Western Gas Partners, LP [Member] | Senior Notes [Member] | 5.375% Senior Notes due 2021 [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]      
Debt Instrument [Line Items]      
Fair value [1] 530,647,000 536,252,000  
Western Gas Partners, LP [Member] | Senior Notes [Member] | 4.000% Senior Notes due 2022 [Member]      
Debt Instrument [Line Items]      
Principal 670,000,000 670,000,000  
Carrying value 668,849,000 668,634,000  
Western Gas Partners, LP [Member] | Senior Notes [Member] | 4.000% Senior Notes due 2022 [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]      
Debt Instrument [Line Items]      
Fair value [1] 684,043,000 681,723,000  
Western Gas Partners, LP [Member] | Senior Notes [Member] | 2.600% Senior Notes due 2018 [Member]      
Debt Instrument [Line Items]      
Principal 350,000,000 350,000,000  
Carrying value 349,684,000 349,188,000  
Western Gas Partners, LP [Member] | Senior Notes [Member] | 2.600% Senior Notes due 2018 [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]      
Debt Instrument [Line Items]      
Fair value [1] 350,631,000 351,531,000  
Western Gas Partners, LP [Member] | Senior Notes [Member] | 5.450% Senior Notes due 2044 [Member]      
Debt Instrument [Line Items]      
Principal 600,000,000 600,000,000 $ 200,000,000
Carrying value 593,234,000 593,132,000  
Western Gas Partners, LP [Member] | Senior Notes [Member] | 5.450% Senior Notes due 2044 [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]      
Debt Instrument [Line Items]      
Fair value [1] 637,827,000 615,753,000  
Western Gas Partners, LP [Member] | Senior Notes [Member] | 3.950% Senior Notes due 2025 [Member]      
Debt Instrument [Line Items]      
Principal 500,000,000 500,000,000  
Carrying value 491,885,000 490,971,000  
Western Gas Partners, LP [Member] | Senior Notes [Member] | 3.950% Senior Notes due 2025 [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]      
Debt Instrument [Line Items]      
Fair value [1] 500,885,000 492,499,000  
Western Gas Partners, LP [Member] | Senior Notes [Member] | 4.650% Senior Notes due 2026 [Member]      
Debt Instrument [Line Items]      
Principal 500,000,000 500,000,000  
Carrying value 495,245,000 494,802,000  
Western Gas Partners, LP [Member] | Senior Notes [Member] | 4.650% Senior Notes due 2026 [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]      
Debt Instrument [Line Items]      
Fair value [1] $ 520,144,000 $ 518,441,000  
[1] Fair value is measured using the market approach and Level 2 inputs.