Segment Information - MidAmerican Funding (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) TheNumberOfReportableSegments OperatingSegments	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | OperatingSegments	8
Revenues	$ 20,952	$ 19,844	$ 19,787
Operating income (loss)	4,291	4,150	4,072
Interest expense	2,021	1,912	1,838
Income tax (benefit) expense	308	(598)	(583)
Net income (loss) attributable to parent	6,943	2,950	2,568
Payments to Acquire Property, Plant, and Equipment	6,765	7,364	6,241
Assets	127,316	100,051	92,189
Goodwill	$ 11,506	9,722	9,595
MidAmerican Funding, LLC and Subsidiaries [Member]
Segment Reporting Information [Line Items]
Number of Reportable Segments | TheNumberOfReportableSegments	2
Revenues	$ 2,728	2,927	3,053
Depreciation and amortization	716	639	609
Operating income (loss)	454	549	550
Interest expense	322	302	247
Income tax (benefit) expense	(574)	(377)	(262)
Net income (loss) attributable to parent	818	781	669
Payments to Acquire Property, Plant, and Equipment	1,836	2,810	2,332
Assets	22,711	21,840	19,202
Goodwill	1,270	1,270
MidAmerican Funding, LLC and Subsidiaries [Member] | Electricity US Regulated
Segment Reporting Information [Line Items]
Revenues	2,139	2,237	2,283
Depreciation and amortization	667	593	565
Operating income (loss)	384	473	469
Interest expense	281	259	208
Income tax (benefit) expense	(584)	(384)	(273)
Net income (loss) attributable to parent	780	739	628
Payments to Acquire Property, Plant, and Equipment	1,704	2,684	2,223
Assets	21,083	20,284	17,702
Goodwill	1,191
MidAmerican Funding, LLC and Subsidiaries [Member] | Natural Gas US Regulated
Segment Reporting Information [Line Items]
Revenues	573	660	754
Depreciation and amortization	49	46	44
Operating income (loss)	64	71	81
Interest expense	23	22	19
Income tax (benefit) expense	14	12	16
Net income (loss) attributable to parent	45	52	54
Payments to Acquire Property, Plant, and Equipment	132	126	109
Assets	1,623	1,547	1,485
Goodwill	79
MidAmerican Funding, LLC and Subsidiaries [Member] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenues	16	30	16
Operating income (loss)	6	5	0
Interest expense	18	21	20
Income tax (benefit) expense	(4)	(5)	(5)
Net income (loss) attributable to parent	(7)	(10)	(13)
Assets	$ 5	$ 9	$ 15