Balance Sheet Components Pension and Other Postretirement Benefits (Details) - Pension Plan [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 4	$ 4	$ 8	$ 8
Interest cost	8	9	16	17
Expected return on plan assets	(11)	(10)	(22)	(20)
Amortization of net actuarial loss	4	2	8	5
Net periodic benefit cost	$ 5	$ 5	$ 10	$ 10