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Earnings Per Share (Tables) | 3 Months Ended
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Mar. 31, 2012
Components of Earnings per Share [Abstract] |
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] | Components of basic and diluted earnings per share were as follows:
| Three Months Ended March 31,
| 2012 |  | 2011
Numerator (in millions): |  |  |
Net income attributable to Portland General Electric Company common shareholders | $ | 49 |  |  | $ | 69 |
Denominator (in thousands): |  |  |
Weighted-average common shares outstanding - basic | 75,423 |  |  | 75,318 |
Dilutive effect of unvested restricted stock units and employee stock purchase plan shares | 20 |  |  | 19 |
Weighted-average common shares outstanding - diluted | 75,443 |  |  | 75,337 |
Earnings per share - basic and diluted | $ | 0.65 |  |  | $ | 0.92 |

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- Definition Tabular disclosure of an entity's basic and diluted earnings per share calculations. + References No definition available. + Details
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