v3.26.1
REVENUE FROM CONTRACTS WITH CUSTOMERS - Performance Obligation (Details)
$ in Millions
Jun. 30, 2026
USD ($)
Disaggregation of Revenue [Line Items]  
Fixed performance obligations $ 186
APPALACHIAN POWER COMPANY  
Disaggregation of Revenue [Line Items]  
Fixed performance obligations 77
INDIANA MICHIGAN POWER COMPANY  
Disaggregation of Revenue [Line Items]  
Fixed performance obligations 18
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-07-01  
Disaggregation of Revenue [Line Items]  
Fixed performance obligations $ 44
Revenue, remaining performance obligation, expected timing of satisfaction, period 6 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-07-01 | APPALACHIAN POWER COMPANY  
Disaggregation of Revenue [Line Items]  
Fixed performance obligations $ 8
Revenue, remaining performance obligation, expected timing of satisfaction, period 6 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-07-01 | INDIANA MICHIGAN POWER COMPANY  
Disaggregation of Revenue [Line Items]  
Fixed performance obligations $ 2
Revenue, remaining performance obligation, expected timing of satisfaction, period 6 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01  
Disaggregation of Revenue [Line Items]  
Fixed performance obligations $ 87
Revenue, remaining performance obligation, expected timing of satisfaction, period 2 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01 | APPALACHIAN POWER COMPANY  
Disaggregation of Revenue [Line Items]  
Fixed performance obligations $ 32
Revenue, remaining performance obligation, expected timing of satisfaction, period 2 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01 | INDIANA MICHIGAN POWER COMPANY  
Disaggregation of Revenue [Line Items]  
Fixed performance obligations $ 9
Revenue, remaining performance obligation, expected timing of satisfaction, period 2 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01  
Disaggregation of Revenue [Line Items]  
Fixed performance obligations $ 39
Revenue, remaining performance obligation, expected timing of satisfaction, period 2 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01 | APPALACHIAN POWER COMPANY  
Disaggregation of Revenue [Line Items]  
Fixed performance obligations $ 25
Revenue, remaining performance obligation, expected timing of satisfaction, period 2 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01 | INDIANA MICHIGAN POWER COMPANY  
Disaggregation of Revenue [Line Items]  
Fixed performance obligations $ 5
Revenue, remaining performance obligation, expected timing of satisfaction, period 2 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2031-01-01  
Disaggregation of Revenue [Line Items]  
Fixed performance obligations $ 16
Revenue, remaining performance obligation, expected timing of satisfaction, period
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2031-01-01 | APPALACHIAN POWER COMPANY  
Disaggregation of Revenue [Line Items]  
Fixed performance obligations $ 12
Revenue, remaining performance obligation, expected timing of satisfaction, period
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2031-01-01 | INDIANA MICHIGAN POWER COMPANY  
Disaggregation of Revenue [Line Items]  
Fixed performance obligations $ 2
Revenue, remaining performance obligation, expected timing of satisfaction, period