Balance Sheet Components Pension and Other Postretirement Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 3	$ 3	$ 6	$ 6
Interest cost	8	7	16	14
Expected return on plan assets	(10)	(10)	(20)	(20)
Amortization of net actuarial loss	4	2	8	4
Net periodic benefit cost	5	2	10	4
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	0	0	0	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	0	0	1	1
Expected return on plan assets	0	0	0	0
Amortization of net actuarial loss	0	0	0	0
Net periodic benefit cost	$ 0	$ 0	$ 1	$ 1