Fair Value Measurements - MidAmerican Funding - Debt (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 39,353	$ 36,774
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	46,004	39,398
MidAmerican Funding, LLC and Subsidiaries [Domain]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	7,448	5,619
Long-term Debt, Fair Value		$ 5,941
MidAmerican Funding, LLC and Subsidiaries [Domain] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	$ 8,599