Related Party Transactions with Duke Energy (Details) - USD ($) $ in Millions		2 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Oct. 31, 2016
Related Party Transaction [Line Items]
Receivables from affiliated companies	[1]	$ 7.2		$ 7.0
Accounts payable to affiliated companies	[1],[2]	10.5		8.7
Revenue, Net		321.7	$ 259.6
Duke Energy
Related Party Transaction [Line Items]
Receivables from affiliated companies		7.2		7.0
Accounts payable to affiliated companies		8.1		$ 6.3
Revenue, Net		13.5	$ 13.4
Related party expenses		$ 1.6

[1] See Note 9 for details on related party transactions with Duke Energy.

[2] See Note 11 for amounts attributable to investments in unconsolidated affiliates.