Statement of Shareholders' Equity (Statement) - USD ($) $ in Millions	Total	Equity	AOCI Attributable to Parent [Member]	Other Additional Capital [Member]	Equity	AOCI Attributable to Parent [Member]	Operating Segments [Member] Utility [Member]	Common Stock [Member]	Other Additional Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]
Shares, Issued								(1)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 148.9							$ 0.0	$ 2,840.4	$ (4.6)	$ (2,686.9)
Other Comprehensive Income (Loss), Net of Tax	(0.2)
Net Income (Loss) Attributable to Parent	2.6
Other Comprehensive Income (Loss), Net of Tax	(0.4)
Net income	12.8
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	12.4
Net Income (Loss) Attributable to Parent	12.8						$ 24.5
Proceeds from Contributions from Parent	130.0
Shares, Issued								(1)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	151.3							$ 0.0	2,840.4	(4.8)	(2,684.3)
Other Comprehensive Income (Loss), Net of Tax	(0.2)
Net income	10.2
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	10.0
Net Income (Loss) Attributable to Parent	10.2						15.1
Proceeds from Contributions from Parent	130.0								130.0
Shares, Issued								(1)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	291.3							$ 0.0	2,970.4	(5.0)	(2,674.1)
Shares, Issued								(1)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	362.1							$ 0.0	3,040.5	(5.3)	(2,673.1)
Other paid-in capital	3,040.5
Accumulated other comprehensive income	(5.3)
Retained Earnings (Accumulated Deficit)	(2,673.1)
Net Income (Loss) Attributable to Parent	2.7
Other Comprehensive Income (Loss), Net of Tax	0.0
Net income	5.0						16.2
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	5.0
Net Income (Loss) Attributable to Parent	3.4
Proceeds from Contributions from Parent	0.0
Shares, Issued								(1)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	364.8							$ 0.0	3,040.5	(5.3)	(2,670.4)
Other Comprehensive Income (Loss), Net of Tax	0.0
Net income	2.3						$ 5.5
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	2.3
Net Income (Loss) Attributable to Parent	0.7
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	(0.2)		$ 2.7			$ 17.5
Shares, Issued								0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	393.4			$ (3,040.5)				$ 0.0	$ 0.0	$ 14.7	$ (2,669.7)
Other paid-in capital	3,048.4
Accumulated other comprehensive income	14.7
Retained Earnings (Accumulated Deficit)	(2,669.7)
Members' Equity	3,048.4	$ 10.6			$ 3,040.5
AOCI Tax, Attributable to Parent	$ 28.1