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Commitments And Contingencies (MPG Site Estimated Future Costs And Recorded Liabilities) (Details) - Natural Gas Processing Plant [Member]
$ in Millions
3 Months Ended
Mar. 31, 2024
USD ($)
Commitments and Contingencies [Line Items]  
Current and non-current environmental liabilities $ 13
IPL [Member]  
Commitments and Contingencies [Line Items]  
Current and non-current environmental liabilities 8
WPL [Member]  
Commitments and Contingencies [Line Items]  
Current and non-current environmental liabilities 5
Minimum [Member]  
Commitments and Contingencies [Line Items]  
Range of estimated future costs 8
Minimum [Member] | IPL [Member]  
Commitments and Contingencies [Line Items]  
Range of estimated future costs 6
Minimum [Member] | WPL [Member]  
Commitments and Contingencies [Line Items]  
Range of estimated future costs 2
Maximum [Member]  
Commitments and Contingencies [Line Items]  
Range of estimated future costs 29
Maximum [Member] | IPL [Member]  
Commitments and Contingencies [Line Items]  
Range of estimated future costs 18
Maximum [Member] | WPL [Member]  
Commitments and Contingencies [Line Items]  
Range of estimated future costs $ 11