Segment Information Segment Information - MidAmerican Funding (Details) $ in Millions		3 Months Ended
		Mar. 31, 2019 USD ($) OperatingSegments ReportableSegments	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | OperatingSegments		8
Operating revenue		$ 4,610	$ 4,440
Operating income		919	871
Interest expense		(477)	(466)
Capitalized interest		16	12
Allowance for equity funds		32	21
Other, net		35	30
Income before income tax (benefit) expense and equity income		487	285
Assets		$ 94,545		$ 92,189
MidAmerican Funding, LLC and Subsidiaries [Domain]
Segment Reporting Information [Line Items]
Number of reportable segments | ReportableSegments		2
Operating revenue		$ 842	747
Operating income		116	79
Interest expense		(75)	(63)
Capitalized interest		6	4
Allowance for equity funds		15	10
Other, net		21	10
Income before income tax (benefit) expense and equity income		83	40
Assets	[1]	20,017		19,202
MidAmerican Funding, LLC and Subsidiaries [Domain] | Regulated electric
Segment Reporting Information [Line Items]
Operating revenue		542	469
Operating income		66	36
Assets	[1]	18,564		17,702
MidAmerican Funding, LLC and Subsidiaries [Domain] | Regulated natural gas
Segment Reporting Information [Line Items]
Operating revenue		295	275
Operating income		48	43
Assets	[1]	1,436		1,485
MidAmerican Funding, LLC and Subsidiaries [Domain] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Operating revenue		5	3
Operating income		2	$ 0
Assets	[1]	$ 17		$ 15

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