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Debt and Interest Expense - Debt Outstanding Table (Details) - USD ($)
Dec. 31, 2016
Oct. 31, 2016
Dec. 31, 2015
Debt Instrument [Line Items]      
Total long-term debt principal $ 3,148,000,000   $ 2,720,000,000
Carrying value 3,119,461,000   2,690,651,000
Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]      
Debt Instrument [Line Items]      
Fair value [1] 3,224,199,000   2,492,466,000
WGP RCF [Member] | Revolving Credit Facility [Member]      
Debt Instrument [Line Items]      
Principal 28,000,000   0
Carrying value 28,000,000   0
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   0
Western Gas Partners, LP [Member] | WES RCF [Member] | Revolving Credit Facility [Member]      
Debt Instrument [Line Items]      
Principal 0   300,000,000
Carrying value 0   300,000,000
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] 0   300,000,000
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 494,734,000   493,711,000
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] 536,252,000   513,645,000
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 668,634,000   668,432,000
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] 681,723,000   595,744,000
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 349,188,000   348,706,000
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] 351,531,000   339,293,000
Western Gas Partners, LP [Member] | Senior Notes [Member] | 5.450% Senior Notes due 2044 [Member]      
Debt Instrument [Line Items]      
Principal 600,000,000 $ 200,000,000 400,000,000
Carrying value 593,132,000   389,707,000
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] 615,753,000   321,499,000
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 490,971,000   490,095,000
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] 492,499,000   422,285,000
Western Gas Partners, LP [Member] | Senior Notes [Member] | 4.650% Senior Notes due 2026 [Member]      
Debt Instrument [Line Items]      
Principal 500,000,000   0
Carrying value 494,802,000   0
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] $ 518,441,000   $ 0
[1] Fair value is measured using the market approach and Level 2 inputs.