XML 73 R61.htm IDEA: XBRL DOCUMENT v3.8.0.1
Debt - Additional Information (Detail) - USD ($)
1 Months Ended 3 Months Ended
Feb. 28, 2018
Jan. 31, 2018
Mar. 31, 2018
Feb. 01, 2018
Dec. 31, 2017
Debt Instrument [Line Items]          
Total borrowings at face value     $ 17,754,000,000   $ 17,032,000,000
APC RCF [Member]          
Debt Instrument [Line Items]          
Line of credit, maximum capacity   $ 3,000,000,000      
Line of credit, expiration date   Jan. 23, 2022      
Line of credit, outstanding borrowings     $ 0    
364-Day Credit Facility Due 2017 [Member]          
Debt Instrument [Line Items]          
Line of credit, maximum capacity   $ 2,000,000,000      
Line of credit, expiration date   Jan. 12, 2019      
Debt instrument, term     364 days    
Line of credit, outstanding borrowings     $ 0    
WES RCF [Member]          
Debt Instrument [Line Items]          
Borrowings, credit facility     260,000,000    
Repayments, credit facility     (630,000,000)    
Fair Value, Inputs, Level 2 [Member] | Market Approach Valuation Technique [Member]          
Debt Instrument [Line Items]          
Estimated fair value of total borrowings     18,100,000,000   17,700,000,000
TEUs - senior amortizing notes due 2018 [Member]          
Debt Instrument [Line Items]          
Outstanding borrowings     $ 9,000,000    
Debt instrument, stated interest rate     1.50%    
7.05% Debentures due May 2018          
Debt Instrument [Line Items]          
Outstanding borrowings     $ 114,000,000    
Debt instrument, stated interest rate     7.05%    
8.70% Debentures due March 2019          
Debt Instrument [Line Items]          
Outstanding borrowings     $ 600,000,000    
Debt instrument, stated interest rate     8.70%    
Zero-Coupon Senior Notes [Member]          
Debt Instrument [Line Items]          
Debt Instrument, earliest call date     Oct. 10, 2018    
Zero-Coupon Senior Notes [Member] | Accreted Value at Next Potential Put Date [Member]          
Debt Instrument [Line Items]          
Debt instrument, accreted value     $ 930,000,000    
WES 4.500% Senior Notes due 2028 [Member]          
Debt Instrument [Line Items]          
Borrowings during period     394,000,000    
WES 5.300% Senior Notes due 2048 [Member]          
Debt Instrument [Line Items]          
Borrowings during period     687,000,000    
Western Gas Partners, LP [Member]          
Debt Instrument [Line Items]          
Total borrowings at face value     4,220,000,000   3,490,000,000
Western Gas Partners, LP [Member] | WES RCF [Member]          
Debt Instrument [Line Items]          
Line of credit, maximum capacity $ 1,500,000,000        
Line of credit, expiration date Feb. 26, 2023 Feb. 26, 2020      
Line of credit, outstanding borrowings     0    
Line of credit, expandable maximum capacity $ 2,000,000,000        
Borrowings, credit facility     260,000,000    
Repayments, credit facility     (630,000,000)    
Letters of credit, outstanding     5,000,000    
Line of credit, available borrowing capacity     $ 1,495,000,000    
Western Gas Partners, LP [Member] | Senior Notes 3 [Member]          
Debt Instrument [Line Items]          
Debt instrument, stated interest rate     2.60%    
Total borrowings at face value     $ 350,000,000    
Western Gas Partners, LP [Member] | WES 4.500% Senior Notes due 2028 [Member]          
Debt Instrument [Line Items]          
Debt instrument, stated interest rate     4.50%    
Total borrowings at face value     $ 400,000,000    
Borrowings during period     $ 394,000,000    
Western Gas Partners, LP [Member] | WES 5.300% Senior Notes due 2048 [Member]          
Debt Instrument [Line Items]          
Debt instrument, stated interest rate     5.30%    
Total borrowings at face value     $ 700,000,000    
Borrowings during period     687,000,000    
Western Gas Equity Partners, LP excluding WES [Member]          
Debt Instrument [Line Items]          
Total borrowings at face value [1]     $ 28,000,000   $ 28,000,000
Western Gas Equity Partners, LP excluding WES [Member] | WGP RCF [Member]          
Debt Instrument [Line Items]          
Line of credit, expiration date     Mar. 14, 2019    
Line of credit, outstanding borrowings     $ 28,000,000    
Line of credit, available borrowing capacity   $ 250,000,000 $ 7,000,000 $ 35,000,000  
Line of credit, interest rate     3.88%    
[1] Excludes WES.