Segment Information Segment Information - MEC (Details) $ in Millions	3 Months Ended
	Mar. 31, 2021 USD ($) OperatingSegments ReportableSegments	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | OperatingSegments	8
Operating revenue	$ 6,081	$ 4,527
Operating income	1,333	919
Interest expense	(530)	(483)
Allowance for borrowed funds	14	17
Allowance for equity funds	26	34
Other, net	8	(27)
Income before income tax (benefit) expense and equity income	(246)	507
Assets	$ 127,522		$ 127,316
MidAmerican Energy Company [Member]
Segment Reporting Information [Line Items]
Number of reportable segments | ReportableSegments	2
Operating revenue	$ 1,067	681
Operating income	48	98
Interest expense	(74)	(76)
Allowance for borrowed funds	2	3
Allowance for equity funds	6	8
Other, net	11	(5)
Income before income tax (benefit) expense and equity income	(7)	28
Assets	22,000		21,437
MidAmerican Energy Company [Member] | Electricity Us Regulated Member
Segment Reporting Information [Line Items]
Operating revenue	545	471
Operating income	9	59
Assets	20,272		19,892
MidAmerican Energy Company [Member] | Natural Gas US Regulated Member
Segment Reporting Information [Line Items]
Operating revenue	512	209
Operating income	39	39
Assets	1,725		1,544
MidAmerican Energy Company [Member] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Operating revenue	10	$ 1
Assets	$ 3		$ 1