Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Activities
Net income	$ 588.3	$ 577.4	$ 546.3
Reconciliation to cash
Depreciation and amortization	419.4	400.2	371.7
Deferred income taxes and investment tax credits, net	328.1	312.7	293.2
Contributions to qualified benefit plans	0	0	(100.0)
Change in -
Accounts receivable and accrued revenues	80.7	(162.9)	38.3
Inventories	(71.2)	31.3	21.3
Other current assets	(13.9)	2.8	12.1
Accounts payable	23.7	(14.8)	43.8
Accrued income taxes, net	(11.4)	36.6	116.9
Deferred costs, net	(15.1)	(8.7)	9.2
Other current liabilities	(18.8)	7.2	(14.9)
Other, net	(112.1)	49.2	(164.0)
Cash Provided by Operating Activities	1,197.7	1,231.0	1,173.9
Investing Activities
Capital expenditures	(736.1)	(687.4)	(707.0)
Investment in transmission affiliate	(13.1)	(10.5)	(15.7)
Proceeds from asset sales	13.9	2.5	8.7
Change in restricted cash	0	2.7	42.8
Payments for (Proceeds from) Removal Costs	(25.1)	(37.8)	(38.3)
Other, net	3.6	(15.3)	(20.1)
Cash Used in Investing Activities	(756.8)	(745.8)	(729.6)
Financing Activities
Exercise of stock options	50.3	48.5	49.8
Purchase of common stock	(123.2)	(223.4)	(153.2)
Dividends paid on common stock	(352.0)	(328.9)	(276.3)
Issuance of long-term debt	250.0	251.0	251.8
Retirement and repurchase of long-term debt	(324.3)	(397.2)	(20.3)
Change in short-term debt	80.2	142.8	(275.3)
Other, net	14.0	12.4	0.7
Cash Used in Financing Activities	(405.0)	(494.8)	(422.8)
Change in Cash and Cash Equivalents	35.9	(9.6)	21.5
Cash and Cash Equivalents at Beginning of Year	26.0	35.6	14.1
Cash and Cash Equivalents at End of Year	$ 61.9	$ 26.0	$ 35.6