Segment Information Segment Information - MEC (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) OperatingSegments ReportableSegments	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | OperatingSegments			8
Operating revenue	$ 5,637	$ 5,283	$ 15,070	$ 14,003
Operating income	1,523	1,640	3,366	3,652
Interest expense	(453)	(464)	(1,380)	(1,379)
Capitalized interest	17	14	44	34
Allowance for equity funds	30	24	75	59
Other, net	19	(17)	50	8
Income before income tax (benefit) expense and equity income	1,423	1,232	1,904	2,467
Assets	91,862		$ 91,862		$ 90,208
MidAmerican Energy Company [Member]
Segment Reporting Information [Line Items]
Number of reportable segments | ReportableSegments			2
Operating revenue	832	813	$ 2,295	2,166
Operating income	278	284	444	516
Interest expense	(56)	(54)	(170)	(160)
Capitalized interest	6	4	14	9
Allowance for equity funds	16	11	39	25
Other, net	13	9	34	27
Income before income tax (benefit) expense and equity income	257	254	361	417
Assets	17,388		17,388		16,318
MidAmerican Energy Company [Member] | Regulated electric
Segment Reporting Information [Line Items]
Operating revenue	727	707	1,785	1,677
Operating income	278	287	392	475
Assets	16,066		16,066		14,914
MidAmerican Energy Company [Member] | Regulated natural gas
Segment Reporting Information [Line Items]
Operating revenue	103	103	505	485
Operating income	1	(3)	52	41
Assets	1,322		1,322		1,403
MidAmerican Energy Company [Member] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Operating revenue	2	3	5	4
Operating income	(1)	$ 0	0	$ 0
Assets	$ 0		$ 0		$ 1