Income Taxes - MEC - Components of Net Deferred Income Tax Liability (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Deferred Tax Assets and Liabilities [Line Items]
Regulatory liabilities	$ 834	$ 812
Derivative contracts	83	62
AROs	317	249
Other	815	781
Total deferred income tax assets, net	3,069	2,849
Property-related items	(13,157)	(11,989)
Regulatory assets	(1,446)	(1,374)
Other	(299)	(301)
Total deferred income tax liabilities	(15,754)	(14,363)
Net deferred income tax liability	(12,685)	(11,514)
MidAmerican Energy Company [Member]
Deferred Tax Assets and Liabilities [Line Items]
Regulatory liabilities	327	332
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits	66	68
Derivative contracts	29	30
AROs	214	185
Other	59	59
Total deferred income tax assets, net	695	674
Property-related items	(3,321)	(2,945)
Regulatory assets	(418)	(366)
Other	(17)	(25)
Total deferred income tax liabilities	(3,756)	(3,336)
Net deferred income tax liability	$ (3,061)	$ (2,662)