CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 280.3	$ 241.9
Adjustments to reconcile net income to net cash provided from operating activities
Depreciation and amortization	240.8	230.0
Deferred income taxes and investment tax credits	134.2	62.3
Equity in earnings of unconsolidated affiliates	(79.5)	12.0
Distributions from unconsolidated affiliates	79.9	67.1
Allowance for equity funds used during construction	(9.2)	(5.4)
Stock-based compensation	3.2	3.8
Excess tax benefit on stock-based compensation	0.0	(5.2)
Regulatory assets	(10.5)	12.7
Regulatory liabilities	(9.8)	(13.9)
Other assets	18.0	12.7
Other liabilities	(19.8)	0.1
Change in certain current assets and liabilities
Accounts receivable, net	(51.2)	(33.8)
Accounts receivable - unconsolidated affiliates	(0.7)	0.5
Accrued unbilled revenues	(17.5)	(22.4)
Fuel, materials and supplies inventories	30.9	(25.5)
Fuel clause under recoveries	(0.5)	66.7
Other current assets	(13.1)	(8.9)
Accounts payable	(90.6)	(57.7)
Fuel clause over recoveries	(59.9)	34.5
Other current liabilities	1.9	37.6
Net Cash Provided from Operating Activities	426.9	609.1
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures (less allowance for equity funds used during construction)	(466.7)	(375.0)
Return of capital - equity method investments	25.9	36.9
Proceeds from sale of assets	0.3	2.2
Net Cash Used in Investing Activities	(440.5)	(335.9)
CASH FLOWS FROM FINANCING ACTIVITIES
Dividends paid on common stock	(164.7)	(149.7)
Issuance of common stock	0.0	7.2
Excess tax benefit on stock-based compensation	0.0	5.2
Payment of long-term debt	(110.1)	(0.1)
Increase (decrease) in short-term debt	213.2	(98.0)
Net Cash Used in Financing Activities	(61.6)	(235.4)
NET CHANGE IN CASH AND CASH EQUIVALENTS	(75.2)	37.8
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	75.2	5.5
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 0.0	$ 43.3