Regulatory Matters - MEC - Regulatory Assets (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017
Regulatory Assets [Line Items]
Regulatory assets		$ 2,896	$ 2,761
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided		$ 1,300	1,100
Deferred Income Tax Charge [Member]
Regulatory Assets [Line Items]
Regulatory asset amortization period years	[1]	Various
Asset Retirement Obligation Costs [Member]
Regulatory Assets [Line Items]
Regulatory asset amortization period years		16.8053333333333
Employee benefit plans [Member]
Regulatory Assets [Line Items]
Regulatory asset amortization period years	[2]	15.5135834411384
Unrealized loss on regulated derivative contracts [Member]
Regulatory Assets [Line Items]
Regulatory asset amortization period years		1.8
MidAmerican Energy Company [Member]
Regulatory Assets [Line Items]
Regulatory assets		$ 273	204
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided		$ 300	200
MidAmerican Energy Company [Member] | Asset Retirement Obligation Costs [Member]
Regulatory Assets [Line Items]
Regulatory Asset, Amortization Period	[3]	12 years
Regulatory assets	[3]	$ 160	133
MidAmerican Energy Company [Member] | Employee benefit plans [Member]
Regulatory Assets [Line Items]
Regulatory Asset, Amortization Period	[4]	14 years
Regulatory assets	[4]	$ 62	38
MidAmerican Energy Company [Member] | Unrealized loss on regulated derivative contracts [Member]
Regulatory Assets [Line Items]
Regulatory Asset, Amortization Period		1 year
Regulatory assets		$ 19	6
MidAmerican Energy Company [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets [Line Items]
Regulatory asset amortization period years		Various
Regulatory assets		$ 32	$ 27

[1] Amounts primarily represent 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.

[2] (1)Represents amounts not yet recognized as a component of net periodic benefit cost that are expected to be included in regulated rates when recognized.

[3] (1)Amount predominantly relates to asset retirement obligations for fossil-fueled and wind-powered generating facilities. Refer to Note 11 for a discussion of asset retirement obligations.

[4] (2)Represents amounts not yet recognized as a component of net periodic benefit cost that are expected to be included in regulated rates when recognized.Mi