Property, Plant and Equipment, Net Property, Plant and Equipment - MEC (Details) - MidAmerican Energy Company [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Net, Excluding Construction Work In Progress	$ 13,410	$ 12,328
Public Utilities, Property, Plant and Equipment, Net	$ 14,207	$ 12,821
Regulated Electric [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service	2.60%	2.80%	3.00%
Natural Gas Processing Plant [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service	2.70%	2.90%	2.90%
Regulated Operation [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Plant in Service, Excluding Construction Work In Progress	$ 18,965	$ 17,770
Public Utilities, Property, Plant and Equipment, Accumulated Depreciation	(5,561)	(5,448)
Public Utilities, Property, Plant and Equipment, Net, Excluding Construction Work In Progress	13,404	12,322
Public Utilities, Property, Plant and Equipment, Construction Work in Progress	797	493
Regulated Operation [Member] | Electric Operations [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Generation or Processing	12,107	11,282
Public Utilities, Property, Plant and Equipment, Transmission	1,838	1,726
Public Utilities, Property, Plant and Equipment, Distribution	3,380	3,197
Regulated Operation [Member] | Natural Gas Processing Plant [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Distribution	1,640	1,565
Nonregulated Operation [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Accumulated Depreciation	(1)	(1)
Public Utilities, Property, Plant and Equipment, Net, Excluding Construction Work In Progress	6	6
Gross public utility property, plant and equipment in service	$ 7	$ 7
Minimum [Member] | Regulated Operation [Member] | Electric Operations [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Generation, Useful Life	20 years
Public Utilities, Property, Plant and Equipment, Transmission, Useful Life	52 years
Public Utilities, Property, Plant and Equipment, Distribution, Useful Life	20 years
Minimum [Member] | Regulated Operation [Member] | Natural Gas Processing Plant [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Distribution, Useful Life	29 years
Minimum [Member] | Nonregulated Operation [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Other Property Plant and Equipment, Useful Life	25 years
Maximum [Member] | Regulated Operation [Member] | Electric Operations [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Generation, Useful Life	70 years
Public Utilities, Property, Plant and Equipment, Transmission, Useful Life	75 years
Public Utilities, Property, Plant and Equipment, Distribution, Useful Life	75 years
Maximum [Member] | Regulated Operation [Member] | Natural Gas Processing Plant [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Distribution, Useful Life	75 years
Maximum [Member] | Nonregulated Operation [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Other Property Plant and Equipment, Useful Life	50 years
Electricity Generation Plant, Non-Nuclear [Member] | Regulated Operation [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Change in Accounting Estimates, Impact on Period of Change	$ 3
Change in Accounting Estimates, Impact on Future Periods	$ 34