Summary of Significant Accounting Policies - PacifiCorp - Income Taxes (Details) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014
Deferred Tax Assets and Liabilities [Line Items]
Total regulatory assets		$ 4,285	$ 4,253
Regulatory Liabilities		3,033	2,832
Deferred Income Tax Charge [Member]
Deferred Tax Assets and Liabilities [Line Items]
Total regulatory assets	[1]	1,577	1,468
PacifiCorp [Member]
Deferred Tax Assets and Liabilities [Line Items]
Total regulatory assets		1,685	1,705
Regulatory Liabilities		972	944
Deferred investment tax credit		23	27
PacifiCorp [Member] | Deferred Income Tax Charge [Member]
Deferred Tax Assets and Liabilities [Line Items]
Total regulatory assets	[2]	437	446
PacifiCorp [Member] | Deferred Income Tax Charge [Member]
Deferred Tax Assets and Liabilities [Line Items]
Regulatory Liabilities		$ 12	$ 13

[1] Amounts primarily represent income tax benefits related to state accelerated tax depreciation and certain property-related basis differences that were previously flowed through to customers and will be included in regulated rates when the temporary differences reverse.

[2] (1)Amounts primarily represent income tax benefits and expense related to certain property-related basis differences and other various items that PacifiCorp is required to pass on to its customers.