Short-Term Debt and Credit Facilities - PacifiCorp - Credit Facility (Details) $ in Millions		Dec. 31, 2018 USD ($)		Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	[1]	$ 9,114		$ 9,051
Short-term Debt	[1]	(2,516)		(4,488)
Line of Credit Facility, Amounts Supported	[1]	(543)		(594)
Line of Credit Facility, Remaining Borrowing Capacity	[1]	6,055		3,969
PacifiCorp [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		1,200	[2]	1,000
Short-term Debt		(30)		(80)	$ (270)	$ (20)	$ (20)
Line of Credit Facility, Amounts Supported		(89)		(130)
Line of Credit Facility, Remaining Borrowing Capacity		$ 1,081		$ 790
PacifiCorp [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Debt, Weighted Average Interest Rate		2.85%		1.83%
Debt to capitalization ratio		0.65
PacifiCorp [Member] | Commercial Paper [Member]
Line of Credit Facility [Line Items]
Debt, Weighted Average Interest Rate		2.85%		1.83%
PacifiCorp [Member] | Unsecured credit facility, $600 million, expiring June 2021, extended [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 600
PacifiCorp [Member] | Unsecured credit facility, $600 million, expiring June 2021, increased and extended [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		600
PacifiCorp [Member] | Certain transactions required by third parties [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Amounts Supported		(14)
PacifiCorp [Member] | Tax exempt bond obligations and commodity contract collateral requirement [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Amounts Supported		(170)		$ (216)
Letters of Credit Outstanding, Amount		$ 184		$ 230

[1] (1)The table does not include unused credit facilities and letters of credit for investments that are accounted for under the equity method.

[2] (2) Includes the drawn uncommitted credit facilities totaling $39 million at Northern Powergrid.