CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Operating Activities
Net income	$ 183.6	$ 149.3
Adjustments to reconcile net income to net cash provided by operating activities
Discontinued operations, net of tax	(5.3)	1.2
Depreciation and amortization expense	126.4	124.7
Recoveries and refunds of regulatory assets and liabilities	28.8	14.9
Bad debt expense	14.4	15.1
Pension and other postretirement expense	31.8	35.3
Pension and other postretirement contributions	(64.2)	(247.0)
Deferred income taxes and investment tax credits	144.0	65.4
Equity income, net of dividends	(9.6)	(9.1)
Termination of tolling agreement with Fox Energy Company LLC	(50.0)	0
Other	13.6	3.5
Changes in working capital
Collateral on deposit	(19.6)	(7.5)
Accounts receivable and accrued unbilled revenues	19.8	223.7
Inventories	69.8	111.6
Other current assets	(54.0)	49.6
Accounts payable	41.3	(62.8)
Temporary LIFO liquidation credit	33.4	2.5
Other current liabilities	(56.2)	(38.5)
Net cash provided by operating activities	448.0	431.9
Investing Activities
Capital expenditures	(300.1)	(249.2)
Proceeds from the sale or disposal of assets	3.1	5.9
Capital contributions to equity method investments	(6.8)	(15.5)
Acquisition of Fox Energy Company LLC	(391.6)	0
Acquisitions at Integrys Energy Services	(12.4)	0
Grant received related to Crane Creek Wind Project	69.0	0
Other	(5.6)	(3.6)
Net cash used for investing activities	(644.4)	(262.4)
Financing Activities
Short-term debt, net	150.8	(24.3)
Borrowing on term credit facility	200.0	0
Issuance of long-term debt	104.0	28.0
Repayment of long-term debt	(187.0)	(28.2)
Proceeds from stock option exercises	31.2	28.3
Shares purchased for stock-based compensation	(2.0)	(50.1)
Payment of dividends
Preferred stock of subsidiary	(1.6)	(1.6)
Common stock	(100.7)	(106.0)
Payments made on derivative contracts related to divestitures classified as financing activities	(5.5)	(19.8)
Other	(1.9)	0.1
Net cash provided by (used for) financing activities	187.3	(173.6)
Change in cash and cash equivalents - continuing operations	(9.1)	(4.1)
Change in cash and cash equivalents - discontinued operations
Net cash provided by operating activities	0.3	1.8
Net cash provided by (used for) investing activities	1.6	(0.1)
Net change in cash and cash equivalents	(7.2)	(2.4)
Cash and cash equivalents at beginning of period	27.4	28.1
Cash and cash equivalents at end of period	$ 20.2	$ 25.7