v3.7.0.1
Operating Segments Operating Segments, Identifiable Assets (Details) - USD ($)
$ in Millions
Mar. 31, 2017
Dec. 31, 2016
Mar. 31, 2016
Dec. 31, 2015
Segment Reporting Information        
Cash and cash equivalents $ 35 $ 688 $ 4 $ 16
Assets 5,873 5,860    
Gathering and Processing [Member]        
Segment Reporting Information        
Assets 4,054 3,392    
Terminalling and Transportation        
Segment Reporting Information        
Assets 1,775 1,768    
Corporate and Other [Member]        
Segment Reporting Information        
Assets [1] $ 44 700    
Whiting Assets [Domain]        
Segment Reporting Information        
Cash and cash equivalents   $ 672    
[1] Other consists mainly of $688 million in cash and cash equivalents as of December 31, 2016, of which $672 million was used to fund the acquisition of the North Dakota Gathering and Processing Assets on January 1, 2017, increasing the Gathering and Processing segment’s identifiable assets as of March 31, 2017.