Income Taxes - MEC - Components of Net Deferred Income Tax Liability (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Deferred Tax Assets and Liabilities [Line Items]
Regulatory liabilities	$ 909	$ 834
Derivative contracts	29	83
AROs	326	317
Other	707	815
Total deferred income tax assets, net	3,103	3,069
Property-related items	(14,237)	(13,157)
Regulatory assets	(1,449)	(1,446)
Other	(334)	(299)
Total deferred income tax liabilities	(16,982)	(15,754)
Net deferred income tax liability	(13,879)	(12,685)
MidAmerican Energy Company [Member]
Deferred Tax Assets and Liabilities [Line Items]
Regulatory liabilities	333	327
AROs	66	66
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits	230	214
Other	74	88
Total deferred income tax assets, net	703	695
Property-related items	(3,763)	(3,321)
Regulatory assets	(471)	(418)
Other	(41)	(17)
Total deferred income tax liabilities	(4,275)	(3,756)
Net deferred income tax liability	$ (3,572)	$ (3,061)