Cash and Cash Equivalents and Restricted Cash and Cash Equivalents Supplemental Cash Flow Disclosures - MEC (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Condensed Cash Flow Statements, Captions [Line Items]
Cash and cash equivalents	$ 2,071	$ 1,040
Restricted cash and cash equivalents	217	212
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	2,304	1,268	$ 1,857	$ 883
MidAmerican Energy Company [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash and cash equivalents	100	287
Restricted cash and cash equivalents	28	43
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 128	$ 330	$ 479	$ 56