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Major Customers and Concentration of Credit Risk
 12 Months Ended
Dec. 31, 2019
Risks and Uncertainties [Abstract]  
Major Customers and Concentration of Credit Risk Major Customers and Concentration of Credit Risk

The table below shows, by segment, the percentage of operating revenues as well as total revenues and other income with MPC which is our most significant customer and our largest concentration of credit risk.

 
2019(1)
 
2018(1)
 
2017(1)
Operating revenues(2)
 
 
 
 
 
L&S
91
%
 
94
%
 
92
%
G&P
4
%
 
3
%
 
0
%
Total
56
%
 
50
%
 
37
%
Total revenues and other income
 
 
 
 
 
L&S
88
%
 
90
%
 
90
%
G&P
4
%
 
2
%
 
0
%
Total
54
%
 
48
%
 
36
%
(1)
The percent calculations exclude revenues attributable to volumes shipped by MPC under joint tariffs with third parties, which are treated as third-party revenue for accounting purposes.
(2)
Operating revenues consist of service revenue, service revenue - product related, rental income and product sales.

MPLX has a concentration of trade receivables due from customers in the same industry: MPC, integrated oil companies, independent refining companies and other pipeline companies. These concentrations of customers may impact MPLX’s overall exposure to credit risk as they may be similarly affected by changes in economic, regulatory and other factors. MPLX manages its exposure to credit risk through credit analysis, credit limit approvals and monitoring procedures; and for certain transactions, it may request letters of credit, prepayments or guarantees.