Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2014

Accounting Policies [Abstract]

Straight-Line Depreciation Rates

Provisions at composite straight-line depreciation rates approximate the following percentages for the cost of depreciable property:

	2014	2013	2012
Electric	2.6 %	2.7 %	2.9 %
Gas	1.7 %	1.7 %	1.7 %
Nonregulated	2.4 %	2.3 %	2.3 %