Income Taxes - MidAmerican Funding - Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Components of Income Tax Expense (Benefit) [Line Items]
Current Federal Tax Expense (Benefit)	$ (1,537)	$ (956)	$ (686)
Current State and Local Tax Expense (Benefit)	(121)	(13)	(9)
Current Income Tax Expense (Benefit)	(1,572)	(888)	(591)
Deferred Federal Income Tax Expense (Benefit)	1,438	431	165
Deferred State and Local Income Tax Expense (Benefit)	424	(127)	(131)
Deferred Income Tax Expense (Benefit)	1,883	296	14
Other Tax Expense (Benefit)	(3)	(6)	(6)
Income tax (benefit) expense	308	(598)	(583)
MidAmerican Funding, LLC and Subsidiaries [Member]
Components of Income Tax Expense (Benefit) [Line Items]
Current Federal Tax Expense (Benefit)	(689)	(480)	(280)
Current State and Local Tax Expense (Benefit)	(96)	(49)	(14)
Current Income Tax Expense (Benefit)	(785)	(529)	(294)
Deferred Federal Income Tax Expense (Benefit)	204	164	42
Deferred State and Local Income Tax Expense (Benefit)	8	(11)	(9)
Deferred Income Tax Expense (Benefit)	212	153	33
Other Tax Expense (Benefit)	(1)	(1)	(1)
Income tax (benefit) expense	$ (574)	$ (377)	$ (262)