Balance Sheet Components Schedule of Other Asssets and Other Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other current assets:
Prepaid Expense, Current	$ 43	$ 39
Current deferred income tax asset	0	33
accrued sales tax refund	0	23	$ 0
Margin Deposit Assets	33	11
Assets from price risk management activities	10	6
Other	2	3
Other Assets, Current	88	115
Accrued expenses and other current liabilities:
Regulatory Liability, Current	55	60
Accrued employee compensation and benefits	51	51
Accrued interest payable	25	26
Dividends payable	28	23
Taxes Payable, Current	25	22
Other	75	54
Other Liabilities, Current	$ 259	$ 236