Balance Sheet Components Pension and Other Postretirement Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 4	$ 4
Interest cost	8	9
Expected return on plan assets	(10)	(10)
Amortization of net actuarial loss	5	4
Net periodic benefit cost	7	7
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	0
Interest cost	1	1
Expected return on plan assets	0	0
Amortization of net actuarial loss	0	0
Net periodic benefit cost	$ 2	$ 1