Income Taxes Income Taxes - MidAmerican Funding - Tax Rate Change (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Rate Change [Line Items]
Deferred Tax Liabilities, Net	$ 9,047	$ 8,242
Deferred Income Tax Expense (Benefit)	14	26	$ 1,098
MidAmerican Funding, LLC and Subsidiaries [Domain]
Income Tax Rate Change [Line Items]
Deferred Tax Liabilities, Net	2,319	2,235
Deferred Income Tax Expense (Benefit)	33	$ 335	$ 363
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 Senate File 2417, Rate Effective Starting 2021 [Member] | MidAmerican Funding, LLC and Subsidiaries [Domain]
Income Tax Rate Change [Line Items]
Deferred Tax Liabilities, Net	54
Deferred Income Tax Expense (Benefit)	2
Iowa Senate File 2417, Rate Effective Starting 2021 [Member] | MidAmerican Funding, LLC and Subsidiaries [Domain] | Deferred Income Tax Charge [Member]
Income Tax Rate Change [Line Items]
Increase in Regulatory Liability	$ 56
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] | Tax Year, Current [Member] | MidAmerican Funding, LLC and Subsidiaries [Domain]
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%
IOWA | Maximum [Member] | Iowa Senate File 2417, Rate Effective Starting 2021 [Member] | MidAmerican Funding, LLC and Subsidiaries [Domain]
Income Tax Rate Change [Line Items]
Statutory Income Tax Rate, State and Local, Percent	9.80%