STATEMENTS OF CASH FLOWS (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 280.3	$ 263.3	$ 215.7
Adjustments to reconcile net income to net cash provided from operating activities
Depreciation and amortization	248.7	216.1	208.7
Deferred income taxes and investment tax credits, net	103.3	95.0	118.8
Allowance for equity funds used during construction	(6.2)	(20.4)	(11.4)
Stock-based compensation expense	2.6	3.0	0
Regulatory assets	20.3	14.0	24.1
Regulatory liabilities	(14.8)	(1.9)	(12.4)
Other assets	(4.5)	2.0	4.8
Other liabilities	(28.7)	(62.9)	(55.8)
Change in certain current assets and liabilities
Accounts receivable, net	20.9	(40.1)	3.6
Accrued unbilled revenues	1.9	(2.5)	0.4
Fuel, materials and supplies inventories	6.5	54.0	(37.5)
Gas imbalance assets	0	0.1	0
Fuel clause under recoveries	1.8	(0.8)	(0.7)
Other current assets	(6.6)	(7.6)	(5.2)
Accounts payable	9.7	13.4	41.4
Accounts payable - affiliates	(0.6)	(3.1)	(0.2)
Income taxes payable - parent	(7.1)	23.0	106.6
Fuel clause over recoveries	101.5	(22.2)	(157.6)
Other current liabilities	8.4	26.9	22.4
Net Cash Provided from Operating Activities	737.4	549.3	465.7
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures (less allowance for equity funds used during construction)	(704.4)	(844.5)	(631.6)
Proceeds from sale of assets	0.6	0.6	1.3
Reimbursement of capital expenditures	27.5	49.6	28.2
Net Cash Used in Investing Activities	(676.3)	(794.3)	(602.1)
CASH FLOWS FROM FINANCING ACTIVITIES
Dividends paid on common stock	(75.0)	0	(60.2)
Payment of long-term debt	(0.1)	0	0
Proceeds from long-term debt	0	246.3	246.2
Capital contribution from OGE Energy	0	50.0	0
Changes in advances with parent	14.0	(51.3)	(49.6)
Net Cash Provided from (Used in) Financing Activities	(61.1)	245.0	136.4
NET CHANGE IN CASH AND CASH EQUIVALENTS	0	0	0
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	0	0	0
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 0	$ 0	$ 0