Income Taxes - MidAmerican Funding - Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Components of Income Tax Expense (Benefit) [Line Items]
Current Federal Tax Expense (Benefit)	$ (686)	$ (653)	$ (743)
Current State and Local Tax Expense (Benefit)	(9)	(3)	1
Current Income Tax Expense (Benefit)	(591)	(573)	(687)
Deferred Federal Income Tax Expense (Benefit)	165	(76)	1,164
Deferred State and Local Income Tax Expense (Benefit)	(131)	100	(59)
Deferred Income Tax Expense (Benefit)	14	26	1,098
Other Tax Expense (Benefit)	(6)	(7)	(8)
Income tax (benefit) expense	(583)	(554)	403
MidAmerican Funding, LLC and Subsidiaries [Domain]
Components of Income Tax Expense (Benefit) [Line Items]
Current Federal Tax Expense (Benefit)	(280)	(505)	(485)
Current State and Local Tax Expense (Benefit)	(14)	(31)	(16)
Current Income Tax Expense (Benefit)	(294)	(536)	(501)
Deferred Federal Income Tax Expense (Benefit)	42	338	367
Deferred State and Local Income Tax Expense (Benefit)	(9)	(3)	(4)
Deferred Income Tax Expense (Benefit)	33	335	363
Other Tax Expense (Benefit)	(1)	(1)	(1)
Income tax (benefit) expense	$ (262)	$ (202)	$ (139)