Credit Risk (Details) MMBbls in Millions, MMBTU in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) $ / MMBTU MMBTU MMBbls	Dec. 31, 2018 USD ($) $ / MMBTU MMBTU MMBbls	Dec. 31, 2017
Gas loaned to customers [Abstract]
Gas Balancing Measurement (in MMBtu) | MMBTU	12.8	13.5
Average Market Price Of Gas Assumed | $ / MMBTU	2.08	3.68
Gas Imbalance To Subsidiaries Asset Liability | $	$ 26.6	$ 49.7
Natural Gas Liquids Balancing Volume (in MMBbls) (Less than) | MMBbls	0.0	0.0
Customer Concentration Risk
Concentration Risk [Line Items]
Concentration Risk, Benchmark Description	no customer comprised 10% or more of the Company’s operating revenues	no customer comprised 10% or more of the Company’s operating revenues	no customer comprised 10% or more of the Company’s operating revenues