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Acquisitions and Sales of Other Assets (Purchase Price Calculation) (Details) (USD $)
In Millions, except Share data, unless otherwise specified |
Mar. 31, 2013
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Dec. 31, 2012
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Jul. 02, 2012
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Mar. 31, 2012
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Dec. 31, 2011
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|---|---|---|---|---|---|
| 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 | ||||
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Progress Energy [Member]
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| Significant Acquisitions and Disposals [Line Items] | |||||
| Progress Energy common shares outstanding | 100 | 100 |