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Employee Benefit Plans - MEC - Fair Value Measurements (Details) - USD ($)
$ in Millions
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
United States Pension Plan of US Entity [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets $ 2,489 $ 2,718 $ 2,711  
United States Pension Plan of US Entity [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 1,007 1,302    
United States Pension Plan of US Entity [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 1,370 1,306    
United States Pension Plan of US Entity [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 112 110    
United States Pension Plan of US Entity [Member] | Cash Equivalents [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 31 69    
United States Pension Plan of US Entity [Member] | Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 0 15    
United States Pension Plan of US Entity [Member] | Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 31 54    
United States Pension Plan of US Entity [Member] | Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 0 0    
United States Pension Plan of US Entity [Member] | US Treasury Securities [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 155 166    
United States Pension Plan of US Entity [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 155 166    
United States Pension Plan of US Entity [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 0 0    
United States Pension Plan of US Entity [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 0 0    
United States Pension Plan of US Entity [Member] | Corporate Debt Securities [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 335 268    
United States Pension Plan of US Entity [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 0 0    
United States Pension Plan of US Entity [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 335 268    
United States Pension Plan of US Entity [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 0 0    
United States Pension Plan of US Entity [Member] | Municipal Bonds [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 25 27    
United States Pension Plan of US Entity [Member] | Municipal Bonds [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 0 0    
United States Pension Plan of US Entity [Member] | Municipal Bonds [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 25 27    
United States Pension Plan of US Entity [Member] | Municipal Bonds [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 0 0    
United States Pension Plan of US Entity [Member] | US Government-sponsored Enterprises Debt Securities [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 154 94    
United States Pension Plan of US Entity [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 0 0    
United States Pension Plan of US Entity [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 154 94    
United States Pension Plan of US Entity [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 0 0    
United States Pension Plan of US Entity [Member] | Domestic Equity Securities [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 586 698    
United States Pension Plan of US Entity [Member] | Domestic Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 586 698    
United States Pension Plan of US Entity [Member] | Domestic Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 0 0    
United States Pension Plan of US Entity [Member] | Domestic Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 0 0    
United States Pension Plan of US Entity [Member] | Foreign Equity Securities [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 122 122    
United States Pension Plan of US Entity [Member] | Foreign Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 122 122    
United States Pension Plan of US Entity [Member] | Foreign Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 0 0    
United States Pension Plan of US Entity [Member] | Foreign Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 0 0    
United States Pension Plan of US Entity [Member] | Equity Funds [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [2] $ 965 $ 1,153    
Percentage of Investment Funds Comprised Of Equity Securitites 66.00% 61.00%    
Percentage of Investment Funds Comprised Of Debt Securities 34.00% 39.00%    
Percentage Of Investment Funds Invested in United States Securities 58.00% 64.00%    
Percentage Of Investment Funds Invested In International Securities 42.00% 36.00%    
United States Pension Plan of US Entity [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1],[2] $ 144 $ 301    
United States Pension Plan of US Entity [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1],[2] 821 852    
United States Pension Plan of US Entity [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1],[2] 0 0    
United States Pension Plan of US Entity [Member] | Real Estate Funds [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 47 40    
United States Pension Plan of US Entity [Member] | Real Estate Funds [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 0 0    
United States Pension Plan of US Entity [Member] | Real Estate Funds [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [1] 0 0    
United States Pension Plan of US Entity [Member] | Real Estate Funds [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 47 [1] 40 [1] 31 $ 26
Domestic Other Postretirement Plans [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 662 858 852  
Domestic Other Postretirement Plans [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 401 613    
Domestic Other Postretirement Plans [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 257 240    
Domestic Other Postretirement Plans [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 4 5    
Domestic Other Postretirement Plans [Member] | Cash Equivalents [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 14 [4] 146    
Domestic Other Postretirement Plans [Member] | Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 12 [4] 145    
Domestic Other Postretirement Plans [Member] | Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 2 [4] 1    
Domestic Other Postretirement Plans [Member] | Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 0 [4] 0    
Domestic Other Postretirement Plans [Member] | US Treasury Securities [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 18 17    
Domestic Other Postretirement Plans [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 18 17    
Domestic Other Postretirement Plans [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 0 0    
Domestic Other Postretirement Plans [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 0 0    
Domestic Other Postretirement Plans [Member] | Corporate Debt Securities [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 33 34    
Domestic Other Postretirement Plans [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 0 0    
Domestic Other Postretirement Plans [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 33 34    
Domestic Other Postretirement Plans [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 0 0    
Domestic Other Postretirement Plans [Member] | Municipal Bonds [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 41 43    
Domestic Other Postretirement Plans [Member] | Municipal Bonds [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 0 0    
Domestic Other Postretirement Plans [Member] | Municipal Bonds [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 41 43    
Domestic Other Postretirement Plans [Member] | Municipal Bonds [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 0 0    
Domestic Other Postretirement Plans [Member] | US Government-sponsored Enterprises Debt Securities [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 28 31    
Domestic Other Postretirement Plans [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 0 0    
Domestic Other Postretirement Plans [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 28 31    
Domestic Other Postretirement Plans [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 0 0    
Domestic Other Postretirement Plans [Member] | Domestic Equity Securities [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 216 243    
Domestic Other Postretirement Plans [Member] | Domestic Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 216 243    
Domestic Other Postretirement Plans [Member] | Domestic Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 0 0    
Domestic Other Postretirement Plans [Member] | Domestic Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 0 0    
Domestic Other Postretirement Plans [Member] | Foreign Equity Securities [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 6 6    
Domestic Other Postretirement Plans [Member] | Foreign Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 6 6    
Domestic Other Postretirement Plans [Member] | Foreign Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 0 0    
Domestic Other Postretirement Plans [Member] | Foreign Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3] 0 0    
Domestic Other Postretirement Plans [Member] | Equity Funds [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [5] $ 302 $ 333    
Percentage of Investment Funds Comprised Of Equity Securitites 63.00% 63.00%    
Percentage of Investment Funds Comprised Of Debt Securities 37.00% 37.00%    
Percentage Of Investment Funds Invested in United States Securities 70.00% 69.00%    
Percentage Of Investment Funds Invested In International Securities 30.00% 31.00%    
Domestic Other Postretirement Plans [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3],[5] $ 149 $ 202    
Domestic Other Postretirement Plans [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3],[5] 153 131    
Domestic Other Postretirement Plans [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets [3],[5] 0 0    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 678 730 722  
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 236 281    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 395 409    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 47 40    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Cash Equivalents [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 16 24    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 16 24    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | US Treasury Securities [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 5 8    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 5 8    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Corporate Debt Securities [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 57 29    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 57 29    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Municipal Bonds [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 6 4    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Municipal Bonds [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Municipal Bonds [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 6 4    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Municipal Bonds [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | US Government-sponsored Enterprises Debt Securities [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 27 33    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 27 33    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Domestic Equity Securities [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 130 149    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Domestic Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 130 149    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Domestic Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Domestic Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Foreign Equity Securities [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 40 40    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Foreign Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 40 40    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Foreign Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Foreign Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Equity Funds [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets $ 350 $ 403    
Percentage of Investment Funds Comprised Of Equity Securitites 72.00% 68.00%    
Percentage of Investment Funds Comprised Of Debt Securities 28.00% 32.00%    
Percentage Of Investment Funds Invested in United States Securities 73.00% 74.00%    
Percentage Of Investment Funds Invested In International Securities 27.00% 26.00%    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets $ 61 $ 84    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 289 319    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Real Estate Funds [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 47 40    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Real Estate Funds [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Real Estate Funds [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | United States Pension Plan of US Entity [Member] | Real Estate Funds [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 47 40 31 $ 26
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 249 259 $ 256  
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 186 193    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 63 66    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Cash Equivalents [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 5 4    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 5 4    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | US Treasury Securities [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 5 5    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 5 5    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Corporate Debt Securities [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 12 11    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 12 11    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Municipal Bonds [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 39 40    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Municipal Bonds [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Municipal Bonds [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 39 40    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Municipal Bonds [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | US Government-sponsored Enterprises Debt Securities [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 12 15    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 12 15    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Domestic Equity Securities [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 120 128    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Domestic Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 120 128    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Domestic Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Domestic Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Equity Funds [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets $ 56 $ 56    
Percentage of Investment Funds Comprised Of Equity Securitites 68.00% 69.00%    
Percentage of Investment Funds Comprised Of Debt Securities 32.00% 31.00%    
Percentage Of Investment Funds Invested in United States Securities 32.00% 31.00%    
Percentage Of Investment Funds Invested In International Securities 68.00% 69.00%    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 1 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets $ 56 $ 56    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 2 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets 0 0    
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member] | Equity Funds [Member] | Fair Value, Inputs, Level 3 [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Fair Value of Plan Assets $ 0 $ 0    
[1] Refer to Note 15 for additional discussion regarding the three levels of the fair value hierarchy.
[2] Investment funds are comprised of mutual funds and collective trust funds. These funds consist of equity and debt securities of approximately 66% and 34%, respectively, for 2015 and 61% and 39%, respectively, for 2014. Additionally, these funds are invested in United States and international securities of approximately 58% and 42%, respectively, for 2015 and 64% and 36%, respectively, for 2014.
[3] Refer to Note 15 for additional discussion regarding the three levels of the fair value hierarchy.
[4] In December 2014, PacifiCorp began to migrate funds to cash and cash equivalents in anticipation of the $150 million to be transferred to a fund managed by the UMWA in May 2015 as a result of the other postretirement settlement. Remaining investments were rebalanced to align to PacifiCorp's target investment allocations.
[5] Investment funds are comprised of mutual funds and collective trust funds. These funds consist of equity and debt securities of approximately 63% and 37%, respectively, for 2015 and 63% and 37%, respectively, for 2014. Additionally, these funds are invested in United States and international securities of approximately 70% and 30%, respectively, for 2015 and 69% and 31%, respectively, for 2014.