Balance Sheet Components (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Oct. 22, 2012	Dec. 31, 2011	Dec. 31, 2010
Valuation and Qualifying Accounts Disclosure [Line Items]
Defined Benefit Plan, Transfers Between Measurement Levels	$ 1	$ 0	$ 0
Long Term Debt, Repayment					100
Allowance for Doubtful Accounts Receivable, Current	6	5	6	5		6	5
Finite-Lived Intangible Assets, Accumulated Amortization	169		169			153
Amortization of Intangible Assets	5	5	17	14
Sale Leaseback Transaction, Construction Cost			10
Portion of $370 million credit facility scheduled to terminate in July 2013	360		360
Credit Facilities - $300 million revolver	300		300
Debt Instrument, Covenant Description			0.650
Ratio of Indebtedness to Net Capital	0.503		0.503
Authorized Short-Term Debt	700		700
Borrowings	0		0
Letters of Credit Issued	61		61
Line of Credit Facility, Remaining Borrowing Capacity	$ 599		$ 599