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Regulatory Matters (Tables) | 12 Months Ended
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Dec. 31, 2012
Regulatory Matters [Abstract] |
Regulatory Assets and Liabilities [Table Text Block] |
Regulatory Assets and Liabilities |  |
As of December 31 | 2012 | 2011
Millions |  |
Current Regulatory Assets (a) |  |
Deferred Fuel |  | $22.5 |  |  | $17.5 |
Total Current Regulatory Assets | 22.5 |  | 17.5 |
Non-Current Regulatory Assets |  |
Future Benefit Obligations Under |  |
Defined Benefit Pension and Other Postretirement Plans | 260.7 |  | 292.8 |
Income Taxes | 36.0 |  | 28.6 |
Asset Retirement Obligation | 12.1 |  | 9.8 |
Cost Recovery Riders (b) | 18.5 |  | 0.7 |
PPACA Income Tax Deferral | 5.0 |  | 5.0 |
Conservation Improvement Program | 4.3 |  | 4.6 |
Other | 3.7 |  | 4.4 |
Total Non-Current Regulatory Assets | 340.3 |  | 345.9 |
Total Regulatory Assets |  | $362.8 |  |  | $363.4 |
Non-Current Regulatory Liabilities |  |
Income Taxes |  | $19.5 |  |  | $21.9 |
Plant Removal Obligations | 18.1 |  | 15.0 |
Wholesale and Retail Contra AFUDC | 15.5 |  | 1.5 |
Other | 7.0 |  | 5.1 |
Total Non-Current Regulatory Liabilities |  | $60.1 |  |  | $43.5 |
(a) | Current regulatory assets are included in prepayments and other on our Consolidated Balance Sheet.
(b) | The increase in cost recovery rider regulatory assets in 2012 is primarily due to revenues related to our Bison Wind Energy Center.

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