v3.26.1
Income Taxes (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Income Tax Disclosure [Abstract]        
Income before income taxes (domestic) $ 51 $ 34 $ 136 $ 88
Federal statutory rate impact     29 18
Other     (1) 0
AFUDC equity [1]     (2) (2)
Plant related excess deferred taxes [1]     (1) (1)
State income taxes, net of federal tax effect (b) [2]     8 5
Other     (1) 0
Income tax expense $ 12 $ 8 $ 32 $ 20
Federal statutory rate     21.00% 21.00%
Other     (0.60%) (0.50%)
AFUDC equity [1]     (1.80%) (2.40%)
Plant related excess deferred taxes [1]     (0.90%) (1.40%)
Other [1]     0.30% 0.30%
State income taxes, net of federal tax effect (b) [2]     5.50% 5.20%
Other     0.00% 0.50%
Effective income tax rate     23.50% 22.70%
[1] Regulatory adjustments primarily relate to the credit of plant related excess deferred taxes to customers for tax rate changes as well as the capitalization of AFUDC equity for book purposes only. Income tax benefits associated with the credit of excess deferred taxes are offset by corresponding revenue reductions.
[2] State and local income taxes are primarily Wisconsin state taxes.