CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 393.8	$ 385.0	$ 363.6
Adjustments to reconcile net income to net cash provided from operating activities
Depreciation and amortization	298.6	374.8	307.7
Impairment of assets	0	0.4	6.3
Deferred income taxes and investment tax credits, net	125.9	143.7	166.0
Equity in earnings of unconsolidated affiliates	(101.9)	0	0
Distributions from unconsolidated affiliates	51.7	0	0
Allowance for equity funds used during construction	(6.6)	(6.2)	(20.4)
(Gain) loss on disposition and abandonment of assets	(8.6)	4.2	(2.7)
Gain on insurance proceeds	0	(7.5)	(3.0)
Stock-based compensation	(3.5)	(2.6)	7.8
Regulatory assets	26.8	20.3	14.0
Regulatory liabilities	(32.5)	(14.8)	(1.9)
Other assets	1.3	(6.9)	(7.6)
Other liabilities	(7.0)	(14.3)	(37.4)
Change in certain current assets and liabilities
Accounts receivable, net	(34.0)	27.1	(48.0)
Accrued unbilled revenues	(1.3)	1.9	(2.5)
Income taxes receivable	1.6	1.1	(3.6)
Fuel, materials and supplies inventories	5.1	13.7	54.2
Fuel clause under recoveries	(26.2)	1.8	(0.8)
Other current assets	(4.5)	(8.6)	(8.2)
Accounts payable	56.9	25.1	34.5
Accounts payable - unconsolidated affiliates	3.7	0	0
Fuel clause over recoveries	(108.8)	101.5	(22.2)
Other current liabilities	(7.3)	6.4	38.1
Net Cash Provided from Operating Activities	623.2	1,046.1	833.9
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures (less allowance for equity funds used during construction)	(990.6)	(1,150.6)	(1,270.4)
Investment in unconsolidated affiliates	(2.7)	0	0
Acquisition of gathering assets	0	(78.6)	(200.4)
Proceeds from insurance	0	7.6	7.4
Reimbursement of capital expenditures	0	27.5	49.6
Proceeds from sale of assets	36.3	1.5	18.0
Net Cash Used in Investing Activities	(957.0)	(1,192.6)	(1,395.8)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from long-term debt	247.4	250.0	246.3
Changes in advances with unconsolidated affiliates	129.6	0	0
Contributions from noncontrolling interest partners	107.0	46.2	216.4
Issuance of common stock	14.2	14.3	14.8
Increase in short-term debt	8.7	153.8	132.1
Repayment of line of credit	0	(150.0)	(25.0)
Proceeds from line of credit	0	0	150.0
Purchase of treasury stock	0	(3.4)	(6.2)
Payment of long-term debt	(0.1)	(0.1)	0
Distributions to noncontrolling interest partners	(2.5)	(12.6)	(17.4)
Dividends paid on common stock	(165.5)	(154.5)	(146.8)
Net Cash Provided from Financing Activities	338.8	143.7	564.2
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	5.0	(2.8)	2.3
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	1.8	4.6	2.3
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 6.8	$ 1.8	$ 4.6