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Investments and Restricted Cash and Investments Investments and Restricted Cash and Investments - MEC - (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Investments, Including Equity Method And Restricted Cash And Investments [Line Items]    
Investments and restricted cash and investments $ 3,945 $ 3,367
MidAmerican Energy Company [Member]    
Investments, Including Equity Method And Restricted Cash And Investments [Line Items]    
Decommissioning Fund Investments, Fair Value 460 429
Life Insurance, Corporate or Bank Owned, Amount 184 175
Available-for-sale Securities, Equity Securities 0 26
Other Investments 9 4
Investments and restricted cash and investments $ 653 $ 634
MidAmerican Energy Company [Member] | Domestic Equity Securities [Member]    
Investments, Including Equity Method And Restricted Cash And Investments [Line Items]    
Nuclear Decommissioning Trust Fund Ownership Percentage 54.00% 56.00%
MidAmerican Energy Company [Member] | US Government Corporations and Agencies Securities [Member]    
Investments, Including Equity Method And Restricted Cash And Investments [Line Items]    
Nuclear Decommissioning Trust Fund Ownership Percentage 35.00% 31.00%
MidAmerican Energy Company [Member] | Domestic Corporate Debt Securities [Member]    
Investments, Including Equity Method And Restricted Cash And Investments [Line Items]    
Nuclear Decommissioning Trust Fund Ownership Percentage 8.00% 9.00%
MidAmerican Energy Company [Member] | Other Securities [Member]    
Investments, Including Equity Method And Restricted Cash And Investments [Line Items]    
Nuclear Decommissioning Trust Fund Ownership Percentage 3.00% 4.00%
MidAmerican Energy Company [Member] | Auction Rate Securities [Member]    
Investments, Including Equity Method And Restricted Cash And Investments [Line Items]    
Available-for-sale Debt Securities, Amortized Cost Basis   $ 35
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities $ 3  
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax   $ 3
Available-for-sale securities, realized gains, net of tax $ 3