Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2011

Summary Of Significant Accounting Policies (Tables) [Abstract]

Straight-Line Depreciation Rates

	2011	2010	2009
Electric	3.2%	3.3%	3.6%
Gas	1.6%	1.7%	3.3%
Nonregulated	2.3%	2.3%	2.5%