Income Taxes - MidAmerican Funding - Tax Rate Change (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Rate Change [Line Items]
Deferred Tax Liabilities, Net	$ 11,775	$ 9,653
Deferred Income Tax Expense (Benefit)	1,883	296	$ 14
MidAmerican Funding, LLC and Subsidiaries [Member]
Income Tax Rate Change [Line Items]
Deferred Tax Liabilities, Net	3,052	2,621
Deferred Income Tax Expense (Benefit)	212	$ 153	$ 33
Iowa Senate File 2417, Rate Effective Starting 2021 [Member]
Income Tax Rate Change [Line Items]
Deferred Tax Liabilities, Net	61
Deferred Income Tax Expense (Benefit)	2
Iowa Senate File 2417, Rate Effective Starting 2021 [Member] | Deferred Income Tax Charge [Member]
Income Tax Rate Change [Line Items]
Increase in Regulatory Liability	$ 59
IOWA | Maximum [Member] | Tax Year, Current [Member]
Income Tax Rate Change [Line Items]
Statutory Income Tax Rate, State and Local, Percent	12.00%
IOWA | Maximum [Member] | Iowa Senate File 2417, Rate Effective Starting 2021 [Member]
Income Tax Rate Change [Line Items]
Statutory Income Tax Rate, State and Local, Percent	9.80%