Balance Sheet Components Schedule of Other Asssets and Other Liabilities (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Other current assets:
Current deferred income tax asset	$ 51	$ 33
Assets from price risk management activities	4	19
Income taxes receivable	1	12
Other	37	34
Other Assets, Current	93	98
Accrued expenses and other current liabilities:
Accrued employee compensation and benefits	46	44
Accrued interest payable	23	24
Dividends payable	21	21
Regulatory Liability, Current	12	6
Other	77	62
Other Liabilities, Current	$ 179	$ 157