Consolidated Statements of Changes in Equity - USD ($) $ in Millions	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Stockholders' Equity, beginning balance at Oct. 31, 2015	$ 1,426.3	$ 721.4	$ 705.7	$ (0.8)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	52.0		52.0
Other comprehensive income, net of tax	0.1			0.1
Common stock issuances, including dividend reinvestment and employee benefits	6.7	6.7
Common stock dividends	(26.7)		(26.7)
Stockholders' Equity, ending balance at Dec. 31, 2015	1,458.4	728.1	731.0	(0.7)
Stockholders' Equity, beginning balance at Oct. 31, 2016	1,644.9	859.8	785.3	(0.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	54.1		54.1
Other comprehensive income, net of tax	0.1			0.1
Distributions to parent	(27.0)		(27.0)
Stockholders' Equity, ending balance at Dec. 31, 2016	$ 1,672.1	$ 859.8	$ 812.4	$ (0.1)