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Income Taxes Income Taxes - MEC - Reconciliation of Effective Income Tax Rate (Details)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Schedule of Effective Income Tax Rate Reconciliation [Line Items]      
Federal statutory income tax rate 21.00% 35.00% 35.00%
Effective Income Tax Rate Reconciliation, Tax Credit, Percent (30.00%) (20.00%) (14.00%)
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent 6.00% (3.00%) 1.00%
Effective Income Tax Rate Reconciliation Regulatory Differences (8.00%) (1.00%) (0.00%)
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent (4.00%) (31.00%) (0.00%)
Other, net (1.00%) (1.00%) (2.00%)
Effective income tax rate (30.00%) (22.00%) 14.00%
Years Eligible For Renewable Energy Production Tax Credit 10 years    
MidAmerican Energy Company [Member]      
Schedule of Effective Income Tax Rate Reconciliation [Line Items]      
Federal statutory income tax rate 21.00% 35.00% 35.00%
Effective Income Tax Rate Reconciliation, Tax Credit, Percent (73.00%) (68.00%) (61.00%)
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent (4.00%) (4.00%) (3.00%)
Effective Income Tax Rate Reconciliation Regulatory Differences (5.00%) (7.00%) (3.00%)
Other, net 0.00% (1.00%) 0.00%
Effective income tax rate (60.00%) (43.00%) (32.00%)
Years Eligible For Renewable Energy Production Tax Credit 10 years    
Tax Cuts and Jobs Act of 2017 [Member]      
Schedule of Effective Income Tax Rate Reconciliation [Line Items]      
Federal statutory income tax rate 21.00%    
Tax Cuts and Jobs Act of 2017 [Member] | MidAmerican Energy Company [Member]      
Schedule of Effective Income Tax Rate Reconciliation [Line Items]      
Federal statutory income tax rate 21.00%    
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent 1.00% 2.00% (0.00%)