Annual report pursuant to Section 13 and 15(d)

Transportation and Distribution Revenue - Schedules of Concentration of Risk (Details)

v3.20.4
Transportation and Distribution Revenue - Schedules of Concentration of Risk (Details) - Product and services - Revenue
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Natural gas transportation contracts      
Concentration Risk [Line Items]      
Percentage of revenues 64.30% 67.80% 64.30%
Natural gas distribution contracts      
Concentration Risk [Line Items]      
Percentage of revenues 23.90% 25.50% 26.80%