Regulatory Matters - MEC - Regulatory Liabilities (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Regulatory Liabilities [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		21.00%	35.00%	35.00%
Regulatory liabilities		$ 7,346	$ 7,309
Removal Costs [Member]
Regulatory Liabilities [Line Items]
Regulatory liability amortization period years	[1]	27.5028854080791
Deferred Income Tax Charge [Member]
Regulatory Liabilities [Line Items]
Regulatory liability amortization period years	[2]	Various
Asset Retirement Obligation Costs [Member]
Regulatory Liabilities [Line Items]
Regulatory liability amortization period years		33.6871165644172
Tax Cuts and Jobs Act of 2017 [Member]
Regulatory Liabilities [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		21.00%
MidAmerican Energy Company [Member]
Regulatory Liabilities [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		21.00%	35.00%	35.00%
Regulatory liabilities		$ 1,620	$ 1,661
MidAmerican Energy Company [Member] | Removal Costs [Member]
Regulatory Liabilities [Line Items]
Regulatory liability amortization period years	[3]	29 years
Regulatory liabilities	[3]	$ 708	688
MidAmerican Energy Company [Member] | Deferred Income Tax Charge [Member]
Regulatory Liabilities [Line Items]
Regulatory liability amortization period years	[4]	29 years
Regulatory liabilities	[4]	$ 626	681
MidAmerican Energy Company [Member] | Asset Retirement Obligation Costs [Member]
Regulatory Liabilities [Line Items]
Regulatory liability amortization period years	[4]	34 years
Regulatory liabilities	[4]	$ 160	173
MidAmerican Energy Company [Member] | Transmission MVP CWIP Return [Member]
Regulatory Liabilities [Line Items]
Regulatory liability amortization period years	[5]	54 years
Regulatory liabilities	[5]	$ 36	35
MidAmerican Energy Company [Member] | Regulatory revenue sharing arrangement [Member]
Regulatory Liabilities [Line Items]
Regulatory liability amortization period years	[6]	1 year
Regulatory liabilities	[6]	$ 70	26
MidAmerican Energy Company [Member] | Pension and other postretirement costs [Member]
Regulatory Liabilities [Line Items]
Regulatory liability amortization period years		N/A
Regulatory liabilities	[7]	$ 0	41
MidAmerican Energy Company [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Liabilities [Line Items]
Regulatory liability amortization period years		Various
Regulatory liabilities		$ 20	$ 17
MidAmerican Energy Company [Member] | Tax Cuts and Jobs Act of 2017 [Member]
Regulatory Liabilities [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		21.00%

[1] Amounts represent estimated costs, as accrued through depreciation rates and exclusive of ARO liabilities, of removing regulated property, plant and equipment in accordance with accepted regulatory practices. Amounts are deducted from rate base or otherwise accrue a carrying cost.

[2] (1)Amounts primarily represent income tax liabilities related to the federal tax rate change from 35% to 21% that are probable to be passed on to customers, offset by income tax benefits related to certain property-related basis differences and other various differences that were previously passed on to customers and will be included in regulated rates when the temporary differences reverse. See Note 11 for further discussion of 2017 Tax Reform impacts.

[3] Amounts represent estimated costs, as accrued through depreciation rates and exclusive of ARO liabilities, of removing utility plant in accordance with accepted regulatory practices. Amounts are deducted from rate base or otherwise accrue a carrying cost.(2)

[4] Amount predominantly represents the excess of nuclear decommission trust assets over the related asset retirement obligation. Refer to Note 11 for a discussion of asset retirement obligations.(4)

[5] Represents amounts not yet recognized as a component of net periodic benefit cost that are to be returned to customers in future periods when recognized.(5)

[6] Represents AFUDC accrued on transmission MVPs that is deducted from rate base as a result of the inclusion of related construction work-in-progress in rate base.(6)

[7] Represents current-year accruals under a regulatory arrangement in Iowa in which equity returns exceeding specified thresholds reduce utility plant upon final determination.