Balance Sheet Components Other Current Liabilities (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Accrued employee compensation and benefits	$ 44	$ 46
Accrued interest payable	33	23
Accrued taxes payable	35	21
Accrued dividends payable	22	21
Regulatory liabilities—current	4	12
Other	54	56
Total accrued expenses and other current liabilities	$ 192	$ 179