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Summary of Significant Accounting Policies (Tables)
 12 Months Ended
Dec. 31, 2020
Summary of Significant Accounting Policies [Abstract]  
Estimated average service lives [Table Text Block] Depreciation is provided on PGE’s other classes of plant in service over their estimated average service lives, which are as follows (in years):
Generation, excluding thermal:
Hydro97
Wind31
Transmission58
Distribution46
General13