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Employee Benefit Plans - MEC - Plan Assumptions (Details)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year 6.80% 7.10%  
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate 5.00% 5.00%  
Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate 2025 2025  
United States Non-Union Postretirement Benefit Plans of US Entity, Defined Benefit [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate 4.21% 3.57% 4.01%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate 3.57% 4.01% 4.33%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets 6.44% 6.73% 7.03%
MidAmerican Energy Company [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year 6.80% 7.10%  
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate 5.00% 5.00%  
Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate 2025 2025  
MidAmerican Energy Company [Member] | United States Non-Union Postretirement Benefit Plans of US Entity, Defined Benefit [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate 4.15% 3.50% 3.90%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate 3.50% 3.90% 4.25%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets 6.25% 6.50% 6.75%
Domestic Plan [Member] | Pension Plan [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate 4.25% 3.60% 4.06%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase 2.75% 2.75% 2.75%
Interest Crediting Rates for Cash Balance Plan, First Year 3.38% 2.49% 2.57%
Interest Crediting Rates for Cash Balance Plan, Second Year 3.54% 3.06% 2.57%
Interest crediting rates for cash balance plan 3.38% 2.49% 2.57%
Interest Crediting Rates for Cash Balance Plan, Sixth Year     3.01%
Interest Crediting Rates for Cash Balance Plan, Fifth Year   2.72% 3.01%
Interest Crediting Rates for Cash Balance Plan, Fourth Year 3.56% 2.72% 3.01%
Interest Crediting Rates for Cash Balance Plan, Third Year 3.54% 3.06% 2.57%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate 3.60% 4.06% 4.43%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets 6.36% 6.55% 6.78%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase 2.75% 2.75% 2.75%
Domestic Plan [Member] | MidAmerican Energy Company [Member] | Pension Plan [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate 4.25% 3.60% 4.10%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase 2.75% 2.75% 2.75%
Interest Crediting Rates for Cash Balance Plan, First Year 2.26% 1.44% 1.18%
Interest Crediting Rates for Cash Balance Plan, Second Year 3.40% 2.26% 1.44%
Interest crediting rates for cash balance plan 2.26% 1.44% 1.18%
Interest Crediting Rates for Cash Balance Plan, Sixth Year     2.10%
Interest Crediting Rates for Cash Balance Plan, Fifth Year   1.60% 2.10%
Interest Crediting Rates for Cash Balance Plan, Fourth Year 3.40% 1.60% 2.10%
Interest Crediting Rates for Cash Balance Plan, Third Year 3.40% 2.26% 1.44%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate 3.60% 4.10% 4.50%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets 6.50% 6.75% 7.00%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase 2.75% 2.75% 2.75%
After-tax [Member] | MidAmerican Energy Company [Member] | United States Non-Union Postretirement Benefit Plans of US Entity, Defined Benefit [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets 4.13% 4.81% 5.00%