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Description of Business and Basis of Presentation - Additional Information (Detail)
$ in Millions
3 Months Ended 6 Months Ended 12 Months Ended
Jul. 30, 2019
shares
Mar. 31, 2020
USD ($)
Jun. 30, 2020
USD ($)
Dec. 31, 2019
USD ($)
Description Of Business And Basis Of Presentation [Line Items]        
Goodwill, Impairment Loss     $ 1,814 $ 1,197
Equity Method Investment, Other than Temporary Impairment   $ 1,264 $ 1,264  
Impairment of Intangible Assets, Finite-lived   177    
Number of reportable segments     2  
Impairment of Long-Lived Assets Held-for-use   174    
Impairment Charges   3,429    
G&P        
Description Of Business And Basis Of Presentation [Line Items]        
Goodwill, Impairment Loss   $ 1,814 $ 1,814 $ 1,197
ANDX LP [Member] | Public        
Description Of Business And Basis Of Presentation [Line Items]        
Common Units Conversion Ratio - ANDX to MPLX | shares 1.135      
ANDX LP [Member] | Nonpublic [Member]        
Description Of Business And Basis Of Presentation [Line Items]        
Common Units Conversion Ratio - ANDX to MPLX | shares 1.0328