CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
CURRENT ASSETS
Cash and cash equivalents	$ 1.1		$ 0.0
Accounts receivable, after allowance for doubtful accounts	157.8		153.8
Accrued unbilled revenues	67.6		64.7
Income taxes receivable	8.1		10.9
Fuel inventories	36.5		46.3
Materials and supplies, at average cost	116.2		90.6
Fuel clause under recoveries	0.0		39.5
Other	41.2		24.4
Total current assets	428.5		430.2
OTHER PROPERTY AND INVESTMENTS
Investment in unconsolidated affiliates	397.4		1,151.5
Other	86.7		82.7
Total other property and investments	484.1		1,234.2
PROPERTY, PLANT AND EQUIPMENT
In service	13,296.7		12,771.1
Construction work in progress	145.5		141.6
Total property, plant and equipment	13,442.2		12,912.7
Less: accumulated depreciation	4,067.6		3,868.1
Net property, plant and equipment	9,374.6		9,044.6
DEFERRED CHARGES AND OTHER ASSETS
Regulatory assets	415.6		306.0
Other	16.0		9.3
Total deferred charges and other assets	431.6		315.3
TOTAL ASSETS	10,718.8		11,024.3
Allowance for Doubtful Accounts Receivable	2.6		1.5
CURRENT LIABILITIES
Short-term debt	95.0		112.0
Accounts payable	251.5		194.9
Dividends payable	80.5		77.6
Customer deposits	81.1		83.0
Accrued taxes	55.7		41.9
Accrued interest	40.2		37.9
Accrued compensation	31.1		40.6
Long-term debt due within one year	0.0		0.0
Fuel clause over recoveries	28.6		4.8
Other	33.7		65.2
Total current liabilities	697.4		657.9
LONG-TERM DEBT	3,494.4		3,195.2
DEFERRED CREDITS AND OTHER LIABILITIES
Accrued benefit obligations	231.4		225.0
Deferred income taxes	1,268.6		1,375.8
Accumulated Deferred Investment Tax Credit	10.9		7.1
Regulatory liabilities	1,188.9		1,223.5
Other	195.4		200.3
Total deferred credits and other liabilities	2,895.2		3,031.7
Total liabilities	7,087.0		6,884.8
COMMITMENTS AND CONTINGENCIES (NOTE 15)
STOCKHOLDERS' EQUITY
Common stockholders' equity	1,124.6		1,131.3
Retained earnings	2,544.6		3,036.1
Accumulated other comprehensive loss, net of tax	(32.1)		(27.9)
Stockholders' Equity Attributable to Parent	3,631.8		4,139.5
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	10,718.8		11,024.3
Og and E [Member]
CURRENT ASSETS
Cash and cash equivalents	0.0		0.0
Accounts receivable, after allowance for doubtful accounts	156.3		153.8
Accrued unbilled revenues	67.7		64.7
Advances to parent	272.0		304.8
Fuel inventories	36.5		46.3
Materials and supplies, at average cost	116.2		90.6
Fuel clause under recoveries	0.0		39.5
Other	36.9		19.6
Total current assets	685.6		719.3
OTHER PROPERTY AND INVESTMENTS
Total other property and investments	4.1		4.7
PROPERTY, PLANT AND EQUIPMENT
In service	13,290.6		12,765.0
Construction work in progress	145.5		141.6
Total property, plant and equipment	13,436.1		12,906.6
Less: accumulated depreciation	4,067.6		3,868.1
Net property, plant and equipment	9,368.5		9,038.5
DEFERRED CHARGES AND OTHER ASSETS
Regulatory assets	415.6		306.0
Other	15.2		8.1
Total deferred charges and other assets	430.8		314.1
TOTAL ASSETS	10,489.0		10,076.6
CURRENT LIABILITIES
Accounts payable	236.7		175.0
Customer deposits	81.1		83.0
Accrued taxes	53.3		41.9
Accrued interest	40.2		37.9
Accrued compensation	22.5		29.5
Long-term debt due within one year	0.0		0.0
Fuel clause over recoveries	28.6		4.8
Other	33.5		65.1
Total current liabilities	495.9		437.2
LONG-TERM DEBT	3,494.4		3,195.2
DEFERRED CREDITS AND OTHER LIABILITIES
Accrued benefit obligations	135.4		133.3
Deferred income taxes	1,020.8		951.4
Accumulated Deferred Investment Tax Credit	10.9		7.1
Regulatory liabilities	1,188.9		1,223.5
Other	167.1		170.6
Total deferred credits and other liabilities	2,523.1		2,485.9
Total liabilities	6,513.4		6,118.3
COMMITMENTS AND CONTINGENCIES (NOTE 15)
STOCKHOLDERS' EQUITY
Common stockholders' equity	1,039.5		1,036.6
Retained earnings	2,936.1		2,921.7
Stockholders' Equity Attributable to Parent	3,975.6		3,958.3
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 10,489.0		$ 10,076.6