Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Tables)

12 Months Ended

Sep. 30, 2012

Accounting Policies [Abstract]

Property, Plant, and Equipment Depreciation Rates

Average depreciation rates by asset class are as follows:

Property, Plant, and Equipment Depreciation Rates At September 30 (percent)
	2012	2011	2010
Asset Class
Nuclear	2.71	2.58	2.59
Coal-Fired	5.65	3.80	3.22
Hydroelectric	1.35	1.43	1.43
Gas and oil-fired	3.67	3.70	4.09
Transmission	2.99	3.39	3.40
Other	8.10	7.39	6.03