Regulatory Matters (Tables)

9 Months Ended

Sep. 30, 2011

Regulated Operations [Abstract]

Regulatory Assets and Liabilities [Table Text Block]

Regulatory Assets and Liabilities	September 30, 2011	December 31, 2010
Millions
Current Regulatory Assets (a)
Deferred Fuel	$17.1	$20.6
Total Current Regulatory Assets	17.1	20.6
Non-Current Regulatory Assets
Future Benefit Obligations Under
Defined Benefit Pension and Other Postretirement Benefit Plans	245.3	257.9
Boswell Unit 3 Environmental Rider	—	20.5
Income Taxes	24.5	17.3
Asset Retirement Obligation	9.2	7.8
Medicare Part D	5.0	—
Other	2.9	6.7
Total Non-Current Regulatory Assets	286.9	310.2
Total Regulatory Assets	$304.0	$330.8
Non-Current Regulatory Liabilities
Income Taxes	$21.6	$23.4
Plant Removal Obligations	16.7	16.9
Other	6.3	3.3
Total Non-Current Regulatory Liabilities	$44.6	$43.6

(a) Current regulatory assets are included in prepayments and other on the consolidated balance sheet.