Balance Sheet Components Pension and Other Postretirement Benefits (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 5	$ 3	$ 9	$ 7
Interest cost	8	8	16	17
Expected return on plan assets	(10)	(10)	(20)	(20)
Defined Benefit Plan, Future Amortization of Prior Service Cost (Credit)	0	0	0	0
Amortization of net actuarial loss	5	5	10	9
Net periodic benefit cost	8	6	15	13
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	2	1
Interest cost	1	1	2	2
Expected return on plan assets	(1)	(1)	(1)	(1)
Defined Benefit Plan, Future Amortization of Prior Service Cost (Credit)	0	1	0	1
Amortization of net actuarial loss	0	0	0	0
Net periodic benefit cost	1	2	3	3
Non Qualified Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0
Interest cost	1	1	1	1
Expected return on plan assets	0	0	0	0
Defined Benefit Plan, Future Amortization of Prior Service Cost (Credit)	0	0	0	0
Amortization of net actuarial loss	0	0	0	0
Net periodic benefit cost	$ 1	$ 1	$ 1	$ 1