Balance Sheet Components Pension and Other Postretirement Benefits (Details) (USD $) In Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2011	Mar. 31, 2010	Jun. 30, 2011	Jun. 30, 2010
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 3	$ 3	$ 6	$ 6
Interest cost	7	7	14	14
Expected return on plan assets	(10)	(10)	(20)	(20)
Amortization of net actuarial gain	2	1	4	2
Net periodic benefit cost	2	1	4	2
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 gain	0	1	0	1
Net periodic benefit cost	1	2	3	4
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 gain	0	0	0	0
Net periodic benefit cost	$ 0	$ 0	$ 1	$ 1