Supplemental Cash Flow Disclosures - MidAmerican Funding (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Cash Flow Statements, Captions [Line Items]
Cash and cash equivalents		$ 1,290	$ 1,040
Restricted cash and cash equivalents		140	212
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents		1,445	1,268	$ 883	$ 1,283
Interest paid, net of amounts capitalized		1,855	1,723	1,713
Income taxes received, net	[1]	1,361	850	780
Accrued capital expenditures		801	888	823
MidAmerican Funding, LLC and Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash and cash equivalents		39	288
Restricted cash and cash equivalents		7	43
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents		46	331	57	$ 282
Interest paid, net of amounts capitalized		302	245	218
Income taxes received, net		715	456	511
Accrued capital expenditures		$ 227	337	$ 371
Property, Plant and Equipment [Member] | MidAmerican Funding, LLC and Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Dividend, Noncash, Transfer Of Asset			$ 8

[1] Includes $1,504 million, $942 million and $884 million of income taxes received from Berkshire Hathaway in 2020, 2019 and 2018, respectively.