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Commitments and Contingencies Commitments and Contingencies - MEC - Transmission Rates (Details) - MidAmerican Energy Company [Member] - Electric Transmission [Member]
$ in Millions
6 Months Ended
Jun. 30, 2019
USD ($)
Loss Contingencies [Line Items]  
Public Utilities, Approved Return on Equity Adder, Percentage 0.50%
Unfavorable Regulatory Action [Member]  
Loss Contingencies [Line Items]  
Accrued liability for estimated transmission billings refunds $ 10
Prior to September 2016 [Member]  
Loss Contingencies [Line Items]  
Public Utilities, Approved Return on Equity, Percentage 12.38%
November 2013 to February 2015 [Member]  
Loss Contingencies [Line Items]  
Public Utilities, Approved Return on Equity, Percentage 10.32%
Public Utilities, Intervenor Proposed Return On Equity, Percentage 9.15%
February 2015 through May 2016 [Member]  
Loss Contingencies [Line Items]  
Public Utilities, Intervenor Proposed Return On Equity, Percentage 8.67%