Transactions with Major Customers and Affiliates (Tables)

12 Months Ended

Dec. 31, 2018

Transactions with Major Customers and Affiliates [Abstract]

Schedule of revenue by major customers

Operating revenues received from three of our major customers in 2018, 2017 and 2016 are as follows (in millions):

	2018		2017		2016
Duke Energy Corporation	$	194.5	$	198.4	$	178.9
National Grid	186.1		177.4		166.3
The Southern Company, Inc.	166.2		160.0		69.6