Employee Benefit Plans - MEC - Unrecognized Amounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Before Tax	$ 480	$ 510
Pension Plan [Member] | MidAmerican Energy Company [Member]
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	(1)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Net Gains (Losses), Before Tax	50	14
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Net Prior Service Cost (Credit), Before Tax	(22)	(37)
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Before Tax	35	(16)	$ 43
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Defined Benefit Plan, Net Unamortized Gain (Loss) Arising During Period, Before Tax	(38)	(73)
Defined Benefit Plan, Net Amortization Recognized in Net Periodic Benefit Cost Before Tax	13	(14)
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Arising During Period, Before Tax	51	(59)
Other Postretirement Benefits Plan [Member] | Regulatory Asset, Pension and Other Postretirement Costs [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Before Tax	44	10	55
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Defined Benefit Plan, Net Unamortized Gain (Loss) Arising During Period, Before Tax	23	(52)
Defined Benefit Plan, Net Amortization Recognized in Net Periodic Benefit Cost Before Tax	11	(7)
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Arising During Period, Before Tax	34	(45)
Other Postretirement Benefits Plan [Member] | Regulatory Liability, Pension and Other Postretirement Costs [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Before Tax	(10)	(26)	(12)
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Defined Benefit Plan, Net Unamortized Gain (Loss) Arising During Period, Before Tax	(14)	(21)
Defined Benefit Plan, Net Amortization Recognized in Net Periodic Benefit Cost Before Tax	(2)	(7)
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Arising During Period, Before Tax	16	(14)
Other Postretirement Benefits Plan [Member] | MidAmerican Energy Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Net Gains (Losses), Before Tax	48	23
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Net Prior Service Cost (Credit), Before Tax	(20)	(25)
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Before Tax	28	(2)	5
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Defined Benefit Plan, Net Unamortized Gain (Loss) Arising During Period, Before Tax	26	(11)
Defined Benefit Plan, Net Amortization Recognized in Net Periodic Benefit Cost Before Tax	4	4
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Arising During Period, Before Tax	30	(7)
Other Postretirement Benefits Plan [Member] | MidAmerican Energy Company [Member] | Regulatory Asset, Pension and Other Postretirement Costs [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Before Tax	37	14	18
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Defined Benefit Plan, Net Unamortized Gain (Loss) Arising During Period, Before Tax	20	(7)
Defined Benefit Plan, Net Amortization Recognized in Net Periodic Benefit Cost Before Tax	3	3
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Arising During Period, Before Tax	23	(4)
Other Postretirement Benefits Plan [Member] | MidAmerican Energy Company [Member] | Receivables (Payables) With Affiliates [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Before Tax	(9)	(16)	(13)
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Defined Benefit Plan, Net Unamortized Gain (Loss) Arising During Period, Before Tax	6	(4)
Defined Benefit Plan, Net Amortization Recognized in Net Periodic Benefit Cost Before Tax	1	1
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Arising During Period, Before Tax	7	(3)
Domestic Plan [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Net Gains (Losses), Before Tax	747	649
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Net Prior Service Cost (Credit), Before Tax	0	(3)
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Before Tax	746	642	761
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Defined Benefit Plan, Net Unamortized Gain (Loss) Arising During Period, Before Tax	(151)	94
Defined Benefit Plan, Net Amortization Recognized in Net Periodic Benefit Cost Before Tax	28	25
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Arising During Period, Before Tax	104	(119)
Domestic Plan [Member] | Pension Plan [Member] | Regulatory Asset, Pension and Other Postretirement Costs [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Before Tax	730	665	761
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Defined Benefit Plan, Net Unamortized Gain (Loss) Arising During Period, Before Tax	114	(68)
Defined Benefit Plan, Net Amortization Recognized in Net Periodic Benefit Cost Before Tax	(28)	28
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Arising During Period, Before Tax	65	(96)
Domestic Plan [Member] | Pension Plan [Member] | Regulatory Liability, Pension and Other Postretirement Costs [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Before Tax	0	(43)	(13)
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Defined Benefit Plan, Net Unamortized Gain (Loss) Arising During Period, Before Tax	(43)	(29)
Defined Benefit Plan, Net Amortization Recognized in Net Periodic Benefit Cost Before Tax	0	(1)
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Arising During Period, Before Tax	43	(30)
Domestic Plan [Member] | Pension Plan [Member] | MidAmerican Energy Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Net Gains (Losses), Before Tax	40	(11)
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Net Prior Service Cost (Credit), Before Tax	1	1
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Before Tax	41	(10)	16
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Defined Benefit Plan, Net Unamortized Gain (Loss) Arising During Period, Before Tax	52	(24)
Defined Benefit Plan, Net Amortization Recognized in Net Periodic Benefit Cost Before Tax	(2)	(2)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	1
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Arising During Period, Before Tax	51	(26)
Domestic Plan [Member] | Pension Plan [Member] | MidAmerican Energy Company [Member] | Regulatory Asset, Pension and Other Postretirement Costs [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Before Tax	25	24	22
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Defined Benefit Plan, Net Unamortized Gain (Loss) Arising During Period, Before Tax	2	4
Defined Benefit Plan, Net Amortization Recognized in Net Periodic Benefit Cost Before Tax	(2)	(2)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	1
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Arising During Period, Before Tax	1	2
Domestic Plan [Member] | Pension Plan [Member] | MidAmerican Energy Company [Member] | Regulatory Liability, Pension and Other Postretirement Costs [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Before Tax	0	(41)	(12)
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Defined Benefit Plan, Net Unamortized Gain (Loss) Arising During Period, Before Tax	41	(29)
Defined Benefit Plan, Net Amortization Recognized in Net Periodic Benefit Cost Before Tax	0	0
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Arising During Period, Before Tax	41	(29)
Domestic Plan [Member] | Pension Plan [Member] | MidAmerican Energy Company [Member] | Receivables (Payables) With Affiliates [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Before Tax	16	7	$ 6
Defined Benefit Plan, Reconciliation of Amounts Not Yet Recognized As Components of Net Periodic Benefit Cost [Roll Forward]
Defined Benefit Plan, Net Unamortized Gain (Loss) Arising During Period, Before Tax	9	1
Defined Benefit Plan, Net Amortization Recognized in Net Periodic Benefit Cost Before Tax	0	0
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Arising During Period, Before Tax	$ 9	$ 1