Income Taxes (Tables)

3 Months Ended

Mar. 31, 2022

Income Tax Disclosure [Abstract]

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

Difference between the statutory rate and effective tax rate:

	Three Months Ended March 31
	2022		2021
Federal statutory rate	21.0	%	21.0	%
State tax (net of federal tax effect)	6.2		6.2
Increases (decreases) in tax from:
Plant regulatory differences (a)	(3.7)		(5.1)
Tax credits	(0.7)		(1.1)
Other (net)	0.2		1.0
Effective income tax rate	23.0	%	22.0	%

(a)Regulatory differences for income tax primarily relate to the credit of excess deferred taxes to customers through the average rate assumption method. Income tax benefits associated with the credit of excess deferred credits are offset by corresponding revenue reductions.