Segment Information Segment Information - MidAmerican Funding (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 Funding, LLC and Subsidiaries [Domain]
Segment Reporting Information [Line Items]
Number of reportable segments | ReportableSegments				2
Operating revenue		832	815	$ 2,297	2,170
Operating income		278	284	444	517
Interest expense		(61)	(59)	(185)	(177)
Capitalized interest		6	4	14	9
Allowance for equity funds		16	11	39	25
Other, net		12	10	35	28
Income before income tax (benefit) expense and equity income		251	250	347	402
Assets	[1]	18,671		18,671		17,621
MidAmerican Funding, LLC and Subsidiaries [Domain] | Regulated electric
Segment Reporting Information [Line Items]
Operating revenue		727	707	1,785	1,677
Operating income		278	287	392	475
Assets	[1]	17,257		17,257		16,105
MidAmerican Funding, LLC and Subsidiaries [Domain] | Regulated natural gas
Segment Reporting Information [Line Items]
Operating revenue		103	103	505	485
Operating income		1	(3)	52	41
Assets	[1]	1,401		1,401		1,482
MidAmerican Funding, LLC and Subsidiaries [Domain] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Operating revenue		2	5	7	8
Operating income		(1)	$ 0	0	$ 1
Assets	[1]	$ 13		$ 13		$ 34

[1] (1)Consists principally of cash and cash equivalents not included in either the regulated electric or regulated natural gas segments.