Regulatory Matters (Details) - entity		2 Months Ended	3 Months Ended		4 Months Ended	6 Months Ended
	Aug. 08, 2018	Jun. 30, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2017	Jun. 30, 2018
Other Commitments [Line Items]
Approved percentage increase (decrease) in rates		0.30%	0.40%	1.90%	(3.00%)
Number of utilities participating in RRC						6
Rate Increases Within 12 Months [Member]
Other Commitments [Line Items]
Rate increase threshold						8.00%
Rate Increases Within 36 Months [Member]
Other Commitments [Line Items]
Rate increase threshold						20.00%
Subsequent Event [Member] | Retail Customers [Member]
Other Commitments [Line Items]
Approved percentage increase (decrease) in rates	1.80%
Subsequent Event [Member] | Wholesale Customer [Member]
Other Commitments [Line Items]
Approved percentage increase (decrease) in rates	2.90%