Income Taxes - PacifiCorp - Component of Net Deferred Income Tax Liability (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Deferred Tax Assets and Liabilities [Line Items]
Regulatory liabilities	$ 834	$ 812
AROs	317	249
Other	815	781
Total deferred income tax assets, net	3,069	2,849
Property-related items	(13,157)	(11,989)
Regulatory assets	(1,446)	(1,374)
Other	(299)	(301)
Total deferred income tax liabilities	(15,754)	(14,363)
Net deferred income tax liability	(12,685)	(11,514)
PacifiCorp [Member]
Deferred Tax Assets and Liabilities [Line Items]
Regulatory liabilities	374	362
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits	189	184
Deferred Tax Assets, Derivative Instruments And Unamortized Contract Values	94	79
Deferred Tax Assets, Operating Loss and Tax Credit Carryforwards, State and Local	68	68
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Contingencies	67	70
AROs	81	47
Other	88	92
Total deferred income tax assets, net	961	902
Property-related items	(5,030)	(4,780)
Regulatory assets	(639)	(647)
Other	(42)	(56)
Total deferred income tax liabilities	(5,711)	(5,483)
Net deferred income tax liability	$ (4,750)	$ (4,581)