Summary of Significant Accounting Policies Significant Accounting Policies - Income Taxes (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Regulatory assets	$ 1,384		$ 1,835
Regulatory liabilities	934		913
Investment tax credits	32		34
Deferred income taxes [Member]
Regulatory liabilities	21		21
Deferred income taxes [Member]
Regulatory assets	$ 461	[1]	$ 456	[1]

[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.