Balance Sheet Components Pension and Other Postretirement Benefits (Details) - Pension Plan [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 5	$ 4	$ 10	$ 8
Interest cost	7	8	14	16
Expected return on plan assets	(11)	(11)	(22)	(22)
Amortization of net actuarial loss	5	4	10	8
Net periodic benefit cost	$ 6	$ 5	$ 12	$ 10