Variable-Interest Entities - PacifiCorp (Details) - PacifiCorp [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Variable Interest Entity, Not Primary Beneficiary [Member]
Schedule of Equity Method Investments [Line Items]
Variable interest entity, ownership percentage	66.67%
Net Assets	$ 74	$ 81
Jim Bridger Unit Nos 1 thru 4 [Member]
Schedule of Equity Method Investments [Line Items]
Jointly Owned Utility Plant, Proportionate Ownership Share	67.00%
Jim Bridger Unit Nos 1 thru 4 [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Schedule of Equity Method Investments [Line Items]
Jointly Owned Utility Plant, Proportionate Ownership Share	66.67%
Jointly Owned Utility Plant, Joint Owner Share	33.33%
Share of coal production purchased by Company	66.67%
Share of coal production purchased by joint venture partner	33.33%