Balance Sheet Components Regulatory Assets and Liabilities (Details) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
Regulatory Assets, Current [Member]
Regulatory Assets [Line Items]
Price risk management	$ 153	$ 175
Pension and other postretirement plans	0	0
Deferred income taxes	0	0
Deferred broker settlements	12	24
Renewable energy deferral	12	22
Debt reacquisition costs	0	0
Other	7	0
Total regulatory assets	184	221
Noncurrent Regulatory Assets [Member]
Regulatory Assets [Line Items]
Price risk management	142	185
Pension and other postretirement plans	207	213
Deferred income taxes	91	95
Deferred broker settlements	0	0
Renewable energy deferral	0	0
Debt reacquisition costs	22	23
Other	19	28
Total regulatory assets	481	544
Current Regulatory Liabilities [Member]
Regulatory Assets [Line Items]
Asset retirement removal costs	0	0
Asset retirement obligations	0	0
Power Cost Adjustment Mechanism	0	0
Regulatory treatment of income taxes (SB 408)	8	5
Trojan ISFSI pollution control tax credits	9	18
Other	2	2
Total regulatory liabilities	19	25
Noncurrent Regulatory Liabilities [Member]
Regulatory Assets [Line Items]
Asset retirement removal costs	612	588
Asset retirement obligations	34	33
Power Cost Adjustment Mechanism	12	0
Regulatory treatment of income taxes (SB 408)	1	9
Trojan ISFSI pollution control tax credits	5	4
Other	28	23
Total regulatory liabilities	$ 692	$ 657