Balance Sheet Components Pension and Other Postretirement Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 4	$ 3	$ 8	$ 6
Interest cost	8	8	16	16
Expected return on plan assets	10	10	20	20
Amortization of prior service cost	0	0	0	0
Amortization of net actuarial loss	6	4	12	8
Net periodic benefit cost	8	5	16	10
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	1	1
Interest cost	1	1	2	2
Expected return on plan assets	(1)	0	(1)	0
Amortization of prior service cost	(1)	0	(1)	0
Amortization of net actuarial loss	0	0	0	0
Net periodic benefit cost	1	1	3	3
Non Qualified Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0
Interest cost	1	0	1	1
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	0	0	0	0
Amortization of net actuarial loss	0	0	0	0
Net periodic benefit cost	$ 1	$ 0	$ 1	$ 1