CONSOLIDATED BALANCE SHEETS (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Assets
Cash and cash equivalents	$ 28.1	$ 179.0
Collateral on deposit	50.9	33.3
Accounts receivable and accrued unbilled revenues, net of reserves of $47.1 and $41.9, respectively	737.7	832.1
Inventories	252.3	247.9
Assets from risk management activities	227.2	236.9
Regulatory assets	125.1	117.9
Deferred income taxes	94.2	67.7
Prepaid taxes	209.6	269.9
Other current assets	78.2	65.7
Current assets	1,803.3	2,050.4
Property, plant, and equipment, net of accumulated depreciation of $3,018.7 and $2,900.2, respectively	5,199.1	5,013.4
Regulatory assets	1,658.5	1,495.1
Assets from risk management activities	64.4	89.4
Goodwill	658.4	642.5
Other long-term assets	599.5	526.0
Total assets	9,983.2	9,816.8
Liabilities and Equity
Short-term debt	303.3	10.0
Current portion of long-term debt	250.0	476.9
Accounts payable	426.6	453.0
Liabilities from risk management activities	311.6	289.6
Accrued taxes	70.5	90.2
Regulatory liabilities	67.5	75.7
Other current liabilities	217.2	262.4
Current liabilities	1,646.7	1,657.8
Long-term debt	1,872.0	2,161.6
Deferred income taxes	1,070.7	860.5
Deferred investment tax credits	44.0	45.2
Regulatory liabilities	332.5	316.2
Environmental remediation liabilities	615.1	643.9
Pension and other postretirement benefit obligations	749.3	603.4
Liabilities from risk management activities	102.0	99.7
Asset retirement obligations	397.2	320.9
Other long-term liabilities	141.1	150.6
Long-term liabilities	5,323.9	5,202.0
Commitments and contingencies
Common stock - $1 par value; 200,000,000 shares authorized; 78,287,906 shares issued; 77,904,935 shares outstanding	78.3	77.8
Additional paid-in capital	2,579.1	2,540.4
Retained earnings	363.6	350.8
Accumulated other comprehensive loss	(42.5)	(44.7)
Shares in deferred compensation trust	(17.1)	(18.5)
Total common shareholders' equity	2,961.4	2,905.8
Preferred stock of subsidiary - $100 par value; 1,000,000 shares authorized; 511,882 shares issued; 510,495 shares outstanding	51.1	51.1
Noncontrolling interest in subsidiaries	0.1	0.1
Total liabilities and equity	$ 9,983.2	$ 9,816.8