Summary of Significant Accounting Policies - PacifiCorp - Allowance for Doubtful Accounts (Details) - PacifiCorp [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Allowance for Doubtful Accounts [Line Items]
Allowance for doubtful accounts	$ 8	$ 8	$ 10
Accounts Receivable, Credit Loss Expense (Reversal)	18	13	12
Accounts Receivable, Allowance for Credit Loss, Writeoff	(9)	(13)	(14)
Allowance for doubtful accounts	$ 17	$ 8	$ 8