v3.26.3
Revenue (Narrative) (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Dec. 31, 2025
Disaggregation of Revenue [Line Items]          
Bad debt expense $ 9 $ 10 $ 29 $ 30  
Unbilled receivables 437   437   $ 659
Consumers Energy Company          
Disaggregation of Revenue [Line Items]          
Bad debt expense 9 $ 10 29 $ 30  
Unbilled receivables $ 437   $ 437   $ 659