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Income Taxes (Details) - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Dec. 31, 2017
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]      
Federal statutory income tax rate 21.00% 35.00% 35.00%
Effective Income Tax Rate Reconciliation, Tax Credit, Percent (45.00%) (16.00%)  
State income tax, net of federal income tax benefit (30.00%) (5.00%)  
Income tax effect of foreign income (16.00%) (5.00%)  
Effects of ratemaking (8.00%) (1.00%)  
Equity income 1.00% 1.00%  
Other (1.00%) (0.00%)  
Effective income tax rate (78.00%) 9.00%  
Recognized production tax credits $ 29    
Production Tax Credit Carryforwards [Abstract]      
Years eligible for federal renewable energy production tax credit 10 years    
Related Party Tax Expense [Abstract]      
Related party transaction, cash received for income taxes, net $ 0 $ 0  
Tax Cuts and Jobs Act of 2017 [Member]      
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]      
Federal statutory income tax rate 21.00%    
PacifiCorp [Member]      
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]      
Federal statutory income tax rate 21.00% 35.00% 35.00%
Effective Income Tax Rate Reconciliation, Tax Credit, Percent (5.00%) (5.00%)  
State income tax, net of federal income tax benefit (4.00%) (3.00%)  
Effects of ratemaking (4.00%) 1.00%  
Other (2.00%) (2.00%)  
Effective income tax rate (14.00%) (32.00%)  
Production Tax Credit Carryforwards [Abstract]      
Years eligible for federal renewable energy production tax credit 10 years    
PacifiCorp [Member] | Tax Cuts and Jobs Act of 2017 [Member]      
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]      
Federal statutory income tax rate 21.00%