Balance Sheet Components Other Current Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Regulatory liabilities—current	$ 57	$ 55
Accrued employee compensation and benefits	42	51
Accrued interest payable	40	25
Accrued dividends payable	28	28
Accrued taxes payable	30	25
Other	71	75
Total accrued expenses and other current liabilities	$ 268	$ 259