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Income Tax
 3 Months Ended
Mar. 31, 2013
Disclosure Income Tax [Abstract]  
Income Tax Disclosure [Text Block]
8. INCOME TAX
The effective income tax rate for the three months ended March 31, 2013 and 2012 varied from the combined federal and state statutory tax rates principally due to the following:

March 31,

2013
 
2012
Federal statutory tax rate
35.0
 %
 
35.0
 %
Increase (decrease):


 


Current state income tax, net of federal tax benefit
4.7

 
4.6

Amortization of investment and energy tax credits
(0.3
)
 
(0.3
)
Differences required to be flowed-through by regulatory commissions
2.4

 
1.6

Gains on company and trust-owned life insurance
(0.3
)
 
(0.4
)
Other, net
(0.7
)
 
0.2

Effective income tax rate
40.8
 %
 
40.7
 %


See Note 9 in the 2012 Form 10-K for more detail on income taxes and effective tax rates.