Exit Activities and Asset Sales (Narrative) (Details) $ in Millions	1 Months Ended		6 Months Ended	12 Months Ended			31 Months Ended
	Jan. 31, 2025 MW	Apr. 30, 2024 USD ($)	Jun. 30, 2025 USD ($)	Dec. 31, 2024 USD ($) MW	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2024 USD ($)
Wind Project
Restructuring Cost and Reserve [Line Items]
Noncontrolling interest capacity (in MW) | MW				100
Wind Project | Forecast
Restructuring Cost and Reserve [Line Items]
Proceeds from sale of noncontrolling interest			$ 40
Solar Projects | Forecast
Restructuring Cost and Reserve [Line Items]
Proceeds from sale of noncontrolling interest			$ 10
Delta Township, Michigan, Solar Project | Forecast
Restructuring Cost and Reserve [Line Items]
Noncontrolling interest capacity (in MW) | MW	24
Phillips, Wisconsin, Solar Project | Forecast
Restructuring Cost and Reserve [Line Items]
Noncontrolling interest capacity (in MW) | MW	3
ASP gain
Restructuring Cost and Reserve [Line Items]
Proceeds from sale of ASP business		$ 124		$ 124	$ 0	$ 0
Gain on disposition of assets		$ 110
Retention Benefits
Restructuring Cost and Reserve [Line Items]
Cost deferred				$ 8	$ 16
Retention Benefits | D.E. Karn Generating Complex and J.H. Campbell Generating Units | Retention Incentive Program
Restructuring Cost and Reserve [Line Items]
Regulatory asset collection period				3 years			3 years
Retention Benefits | J.H. Campbell Generating Units
Restructuring Cost and Reserve [Line Items]
Expected cost				$ 50			$ 50
Retention Benefits | J.H. Campbell Generating Units | Retention Incentive Program
Restructuring Cost and Reserve [Line Items]
Cost deferred							$ 43