Income Taxes - MEC - Components of Net Deferred Income Tax Liability (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Deferred Tax Assets and Liabilities [Line Items]
Regulatory liabilities	$ 1,674	$ 1,707
AROs	232	223
Other	459	450
Total deferred income tax assets, net	2,892	3,417
Property-related items	(10,185)	(9,950)
Regulatory assets	(656)	(651)
Other	(222)	(215)
Total deferred income tax liabilities	(11,939)	(11,659)
Net deferred income tax liability	(9,047)	(8,242)
MidAmerican Energy Company [Member]
Deferred Tax Assets and Liabilities [Line Items]
Regulatory liabilities	405	443
AROs	164	160
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits	47	45
Other	80	57
Total deferred income tax assets, net	696	705
Property-related items	(2,945)	(2,865)
Regulatory assets	(61)	(42)
Other	(12)	(35)
Total deferred income tax liabilities	(3,018)	(2,942)
Net deferred income tax liability	$ (2,322)	$ (2,237)