Balance Sheet Components Other Current Liabilities (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Accrued employee compensation and benefits	$ 39	$ 46
Accrued interest payable	22	23
Accrued taxes payable	24	21
Accrued dividends payable	21	21
Regulatory liabilities—current	7	12
Other	62	56
Total accrued expenses and other current liabilities	$ 175	$ 179