Significant Accounting Policies (Schedule Of Depreciation Rates) (Details)	26 Months Ended	29 Months Ended
	Dec. 31, 2012	Oct. 31, 2010
Minimum [Member] | Steam Production Plant [Member]
Depreciation and amortization rate	4.81%	4.45%
Minimum [Member] | Hydraulic Production Plant [Member]
Depreciation and amortization rate	1.06%	1.22%
Minimum [Member] | Other Production Plant [Member]
Depreciation and amortization rate	3.98%	3.77%
Minimum [Member] | Transmission Plant [Member]
Depreciation and amortization rate	1.58%	1.61%
Minimum [Member] | Distribution Plant [Member]
Depreciation and amortization rate	2.17%	1.95%
Minimum [Member] | General Plant [Member]
Depreciation and amortization rate	1.57%	1.25%
Minimum [Member] | Other Plant [Member]
Depreciation and amortization rate	2.75%	2.75%
Maximum [Member] | Steam Production Plant [Member]
Depreciation and amortization rate	7.04%	5.85%
Maximum [Member] | Hydraulic Production Plant [Member]
Depreciation and amortization rate	3.00%	3.00%
Maximum [Member] | Other Production Plant [Member]
Depreciation and amortization rate	10.15%	10.56%
Maximum [Member] | Transmission Plant [Member]
Depreciation and amortization rate	7.86%	6.67%
Maximum [Member] | Distribution Plant [Member]
Depreciation and amortization rate	9.63%	9.77%
Maximum [Member] | General Plant [Member]
Depreciation and amortization rate	20.00%	26.11%
Maximum [Member] | Other Plant [Member]
Depreciation and amortization rate	2.75%	2.75%