Risk Management and Hedging Activities Risk Management and Hedging Activities - Balance Sheet Location (Details) (Commodity Contract [Member], USD $) In Millions, unless otherwise specified	Sep. 30, 2012		Jun. 30, 2012	Dec. 31, 2011		Sep. 30, 2011	Jun. 30, 2011	Dec. 31, 2010
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Net	$ (130)			$ (264)
Cash collateral, net receivable (payable), offset against derivative positions	67			123
Derivative Assets (Liabilities), at Fair Value, Net	(63)			(141)
Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Net	12			13
Cash collateral, net receivable (payable), offset against derivative positions	0			(2)
Derivative Assets (Liabilities), at Fair Value, Net	12			11
Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Net	5			4
Cash collateral, net receivable (payable), offset against derivative positions	0			0
Derivative Assets (Liabilities), at Fair Value, Net	5			4
Derivative Contracts, Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Net	(105)			(176)
Cash collateral, net receivable (payable), offset against derivative positions	62			86
Derivative Assets (Liabilities), at Fair Value, Net	(43)			(90)
Other Long-term Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Net	(42)			(105)
Cash collateral, net receivable (payable), offset against derivative positions	5			39
Derivative Assets (Liabilities), at Fair Value, Net	(37)			(66)
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	53	[1]		115	[1]
Commodity liabilities	(183)	[1]		(379)	[1]
Derivative, Fair Value, Net	(130)	[1]		(264)	[1]
Net regulatory asset	130		217	264		423	438	487
Not Designated as Hedging Instrument [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	16	[1]		30	[1]
Commodity liabilities	(4)	[1]		(17)	[1]
Derivative, Fair Value, Net	12	[1]		13	[1]
Not Designated as Hedging Instrument [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	6	[1]		7	[1]
Commodity liabilities	(1)	[1]		(3)	[1]
Derivative, Fair Value, Net	5	[1]		4	[1]
Not Designated as Hedging Instrument [Member] | Derivative Contracts, Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	27	[1]		66	[1]
Commodity liabilities	(132)	[1]		(242)	[1]
Derivative, Fair Value, Net	(105)	[1]		(176)	[1]
Not Designated as Hedging Instrument [Member] | Other Long-term Liabilities [Member]
Derivatives, Fair Value [Line Items]
Commodity assets	4	[1]		12	[1]
Commodity liabilities	(46)	[1]		(117)	[1]
Derivative, Fair Value, Net	$ (42)	[1]		$ (105)	[1]

[1] PacifiCorp's commodity derivatives are generally included in rates and as of September 30, 2012 and December 31, 2011, a net regulatory asset of $130 million and $264 million, respectively, was recorded related to the net derivative liability of $130 million and $264 million, respectively.