v2.4.0.6

Acquisitions and Sales of Other Assets (Purchase Price Calculation) (Details) (USD $) In Millions, except Share data, unless otherwise specified | Mar. 31, 2013 | Dec. 31, 2012 | Jul. 02, 2012 | Mar. 31, 2012 | Dec. 31, 2011
--- | --- | --- | --- | --- | ---
Significant Acquisitions and Disposals [Line Items] |  |  |  |  |
Progress Energy common shares outstanding | 706,000,000 | 704,000,000 |  | 446,000,000 | 445,000,000
Exchange ratio |  |  | 87.083% |  |
Fair value of outstanding earned stock compensation awards |  |  | $ 62 |  |
Total estimated purchase price |  |  | $ 18,071 |  |
Progress Energy [Member] |  |  |  |  |
Significant Acquisitions and Disposals [Line Items] |  |  |  |  |
Progress Energy common shares outstanding | 100 | 100 |  |  |

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