CONSOLIDATED BALANCE SHEETS (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
CURRENT ASSETS
Cash and cash equivalents	$ 5.5	$ 6.8
Accounts receivable, less reserve of $1.6 and $1.9, respectively	188.8us-gaap_AccountsReceivableNetCurrent	179.4us-gaap_AccountsReceivableNetCurrent
Accounts receivable - unconsolidated affiliates	5.6	12.4
Accrued unbilled revenues	55.5us-gaap_UnbilledReceivablesCurrent	58.7us-gaap_UnbilledReceivablesCurrent
Income taxes receivable	16.0us-gaap_IncomeTaxesReceivable	5.6us-gaap_IncomeTaxesReceivable
Fuel inventories	58.5us-gaap_InventoryNet	74.4us-gaap_InventoryNet
Materials and supplies, at average cost	78.9us-gaap_OtherInventorySupplies	80.7us-gaap_OtherInventorySupplies
Deferred income taxes	191.4us-gaap_DeferredTaxAssetsNetCurrent	215.8us-gaap_DeferredTaxAssetsNetCurrent
Fuel clause under recoveries	68.3us-gaap_DeferredFuelCost	26.2us-gaap_DeferredFuelCost
Other	37.3us-gaap_OtherAssetsCurrent	34.6us-gaap_OtherAssetsCurrent
Total current assets	705.8us-gaap_AssetsCurrent	694.6us-gaap_AssetsCurrent
OTHER PROPERTY AND INVESTMENTS
Investment in unconsolidated affiliates	1,318.2us-gaap_EquityMethodInvestments	1,298.8us-gaap_EquityMethodInvestments
Other	70.1us-gaap_OtherLongTermInvestments	61.0us-gaap_OtherLongTermInvestments
Total other property and investments	1,388.3us-gaap_OtherInvestments	1,359.8us-gaap_OtherInvestments
PROPERTY, PLANT AND EQUIPMENT
In service	9,983.0	9,183.1
Construction work in progress	115.9us-gaap_ConstructionInProgressGross	468.5us-gaap_ConstructionInProgressGross
Total property, plant and equipment	10,098.9us-gaap_PropertyPlantAndEquipmentGross	9,651.6us-gaap_PropertyPlantAndEquipmentGross
Less accumulated depreciation	3,119.0	2,978.8
Net property, plant and equipment	6,979.9us-gaap_PropertyPlantAndEquipmentNet	6,672.8us-gaap_PropertyPlantAndEquipmentNet
DEFERRED CHARGES AND OTHER ASSETS
Regulatory assets	411.5us-gaap_RegulatoryAssetsNoncurrent	379.1us-gaap_RegulatoryAssetsNoncurrent
Other	42.3	28.4
Total deferred charges and other assets	453.8us-gaap_OtherAssetsNoncurrent	407.5us-gaap_OtherAssetsNoncurrent
TOTAL ASSETS	9,527.8us-gaap_Assets	9,134.7us-gaap_Assets
CURRENT LIABILITIES
Short-term debt	98.0us-gaap_ShortTermBorrowings	439.6us-gaap_ShortTermBorrowings
Accounts payable	179.1us-gaap_AccountsPayableCurrent	251.0us-gaap_AccountsPayableCurrent
Dividends payable	49.9us-gaap_DividendsPayableCurrent	44.7us-gaap_DividendsPayableCurrent
Customer deposits	73.7us-gaap_CustomerDepositsCurrent	70.9us-gaap_CustomerDepositsCurrent
Accrued taxes	39.7us-gaap_TaxesPayableCurrent	39.9us-gaap_TaxesPayableCurrent
Accrued interest	43.0us-gaap_InterestPayableCurrent	43.4us-gaap_InterestPayableCurrent
Accrued compensation	38.2	56.9
Long-term debt due within one year	0us-gaap_LongTermDebtCurrent	100.0us-gaap_LongTermDebtCurrent
Other	51.7us-gaap_OtherLiabilitiesCurrent	47.4us-gaap_OtherLiabilitiesCurrent
Total current liabilities	573.3us-gaap_LiabilitiesCurrent	1,093.8us-gaap_LiabilitiesCurrent
LONG-TERM DEBT	2,755.3us-gaap_LongTermDebtNoncurrent	2,300.1us-gaap_LongTermDebtNoncurrent
DEFERRED CREDITS AND OTHER LIABILITIES
Accrued benefit obligations	315.5	241.5
Deferred income taxes	2,268.3	2,125.3
Regulatory liabilities	263.0us-gaap_RegulatoryLiabilityNoncurrent	234.2us-gaap_RegulatoryLiabilityNoncurrent
Other	108.0us-gaap_OtherLiabilitiesNoncurrent	102.7us-gaap_OtherLiabilitiesNoncurrent
Total deferred credits and other liabilities	2,954.8	2,703.7
Total liabilities	6,283.4us-gaap_Liabilities	6,097.6us-gaap_Liabilities
COMMITMENTS AND CONTINGENCIES (NOTE 14)
STOCKHOLDERS' EQUITY
Common stockholders' equity	1,087.6	1,073.6
Retained earnings	2,198.2	1,991.7
Accumulated other comprehensive loss, net of tax	(41.4)	(28.2)
Total stockholders' equity	3,244.4	3,037.1
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 9,527.8	$ 9,134.7

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Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).