Regulatory Matters - MEC - Regulatory Assets (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014
Regulatory Assets [Line Items]
Regulatory assets		$ 4,155	$ 4,000
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided		$ 2,300	2,600
Deferred Income Tax Charge [Member]
Regulatory Assets [Line Items]
Regulatory asset amortization period years	[1]	26 years
Asset Retirement Obligation Costs [Member]
Regulatory Assets [Line Items]
Regulatory asset amortization period years		8 years
Employee benefit plans [Member]
Regulatory Assets [Line Items]
Regulatory asset amortization period years	[2]	9 years
Unrealized loss on regulated derivative contracts [Member]
Regulatory Assets [Line Items]
Regulatory asset amortization period years		5 years
MidAmerican Energy Company [Member]
Regulatory Assets [Line Items]
Regulatory assets		$ 1,044	908
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided		$ 1,000	904
MidAmerican Energy Company [Member] | Deferred Income Tax Charge [Member]
Regulatory Assets [Line Items]
Regulatory Asset, Amortization Period	[3]	25 years
Regulatory assets	[3]	$ 858	730
MidAmerican Energy Company [Member] | Asset Retirement Obligation Costs [Member]
Regulatory Assets [Line Items]
Regulatory Asset, Amortization Period	[4]	6 years
Regulatory assets	[4]	$ 94	62
MidAmerican Energy Company [Member] | Employee benefit plans [Member]
Regulatory Assets [Line Items]
Regulatory Asset, Amortization Period	[5]	11 years
Regulatory assets	[5]	$ 39	42
MidAmerican Energy Company [Member] | Unrealized loss on regulated derivative contracts [Member]
Regulatory Assets [Line Items]
Regulatory Asset, Amortization Period		1 year
Regulatory assets		$ 20	38
MidAmerican Energy Company [Member] | Other Regulatory Assets (Liabilities) [Member]
Regulatory Assets [Line Items]
Regulatory asset amortization period years		Various
Regulatory assets		$ 33	$ 36

[1] Amounts primarily represent income tax benefits related to state accelerated tax depreciation and certain property-related basis differences that were previously flowed through to customers and will be included in regulated rates when the temporary differences reverse.

[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.

[3] (1)Amounts primarily represent income tax benefits related to state accelerated tax depreciation and certain property-related basis differences that were previously flowed through to customers and will be included in regulated rates when the temporary differences reverse.

[4] (2)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.

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