Segment Information Segment Information - MidAmerican Funding (Details) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) OperatingSegments ReportableSegments	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | OperatingSegments				8
Revenues		$ 4,993	$ 4,554	$ 9,433	$ 8,720
Operating income		972	1,045	1,843	2,012
Interest expense		(461)	(457)	(927)	(915)
Capitalized interest		15	10	27	20
Allowance for equity funds		24	18	45	35
Other, net		1	(1)	31	25
Income before income tax (benefit) expense and equity income		196	644	481	1,235
Assets		90,941		$ 90,941		$ 90,208
MidAmerican Funding, LLC and Subsidiaries [Domain]
Segment Reporting Information [Line Items]
Number of reportable segments | ReportableSegments				2
Electric Domestic Regulated Revenue		589	537	$ 1,058	970
Revenues		718	659	1,465	1,355
Operating income		87	131	166	233
Interest expense		(61)	(59)	(124)	(118)
Capitalized interest		4	3	8	5
Allowance for equity funds		13	8	23	14
Other, net		13	7	23	18
Income before income tax (benefit) expense and equity income		56	90	96	152
Assets	[1]	18,172		18,172		17,621
MidAmerican Funding, LLC and Subsidiaries [Domain] | Regulated Electric [Member]
Segment Reporting Information [Line Items]
Electric Domestic Regulated Revenue		589	537	1,058	970
Operating income		78	125	114	188
Assets	[1]	16,803		16,803		16,105
MidAmerican Funding, LLC and Subsidiaries [Domain] | Regulated Gas [Member]
Segment Reporting Information [Line Items]
Gas Domestic Regulated Revenue		127	120	402	382
Operating income		8	5	51	44
Assets	[1]	1,353		1,353		1,482
MidAmerican Funding, LLC and Subsidiaries [Domain] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Other Revenue, Net		2	2	5	3
Operating income		1	$ 1	1	$ 1
Assets	[1]	$ 16		$ 16		$ 34

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