Income Taxes - MEC - 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 Energy Company [Member]
Components of Income Tax Expense (Benefit) [Line Items]
Current Federal Tax Expense (Benefit)	(684)	(478)	(276)
Current State and Local Tax Expense (Benefit)	(94)	(47)	(12)
Current Income Tax Expense (Benefit)	(778)	(525)	(288)
Deferred Federal Income Tax Expense (Benefit)	201	166	42
Deferred State and Local Income Tax Expense (Benefit)	8	(11)	(8)
Deferred Income Tax Expense (Benefit)	209	155	34
Other Tax Expense (Benefit)	(1)	(1)	(1)
Income tax (benefit) expense	$ (570)	$ (371)	$ (255)