Segment Information Segment Information - MEC (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($) OperatingSegments ReportableSegments	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | OperatingSegments	8
Revenues	$ 4,440	$ 4,166
Operating income	871	967
Interest expense	(466)	(458)
Capitalized interest	12	10
Allowance for equity funds	21	17
Other, net	30	26
Income before income tax (benefit) expense and equity income	285	591
Assets	$ 90,912		$ 90,208
MidAmerican Energy Company [Member]
Segment Reporting Information [Line Items]
Number of reportable segments | ReportableSegments	2
Electric Domestic Regulated Revenue	$ 469	433
Revenues	746	695
Operating income	79	102
Interest expense	(58)	(53)
Capitalized interest	4	2
Allowance for equity funds	10	6
Other, net	9	11
Income before income tax (benefit) expense and equity income	44	68
Assets	16,580		16,318
MidAmerican Energy Company [Member] | Regulated Electric [Member]
Segment Reporting Information [Line Items]
Electric Domestic Regulated Revenue	469	433
Operating income	36	63
Assets	15,254		14,914
MidAmerican Energy Company [Member] | Regulated Gas [Member]
Segment Reporting Information [Line Items]
Gas Domestic Regulated Revenue	275	262
Operating income	43	39
Assets	1,323		1,403
MidAmerican Energy Company [Member] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Other Revenue, Net	2	$ 0
Assets	$ 3		$ 1