XML 161 R132.htm IDEA: XBRL DOCUMENT v3.19.1
Variable Interest Entities (Detail) - USD ($)
$ in Millions
1 Months Ended 12 Months Ended
May 31, 2017
May 31, 2008
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Variable Interest Entity [Line Items]          
Interest income for WES     $ 1,028 $ 1,003 $ 1,022
Western Gas Partners LP [Member] | Variable Interest Entity, Primary Beneficiary [Member]          
Variable Interest Entity [Line Items]          
Note receivable for WES   $ 260      
Debt instrument, term   30 years      
Fixed annual rate   6.50%      
Interest income for WES     17 17 17
Cash payment received $ 37        
Above-market component of swap extensions with Anadarko     $ 52 $ 59 $ 46