Balance Sheet Components Pension and Other Postretirement Benefits (Details) - Pension Plan [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 4	$ 4	$ 13	$ 11
Interest cost	8	8	24	25
Expected return on plan assets	(10)	(9)	(30)	(29)
Amortization of net actuarial loss	5	4	15	13
Net periodic benefit cost	$ 7	$ 7	$ 22	$ 20