Balance Sheet Components Pension and Other Postretirement Benefits (Details) - Pension Plan [Member] - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2016	Jun. 30, 2015
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 4	$ 5	$ 9	$ 8
Interest cost	8	8	16	16
Expected return on plan assets	(10)	(10)	(20)	(20)
Amortization of net actuarial loss	4	5	$ 10	8
Net periodic benefit cost	$ 6	$ 8		$ 12	$ 15