Significant Accounting Policies (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Comprehensive Income [Line Items]
Net Unrealized Gain/(Loss) on Derivaive	$ (4)	$ (4)
Net Unrealized Gain/(Loss) on Investments	(29)	(30)
Benefit Obligations	(127)	(125)
Foreign Currency Translation	2	1
Accumulated Other Comprehensive Loss	(158)	(158)
Current period change, net of tax Net Unrealized Gain/(Loss) on Derivatives Gain (Loss) on Derivatives Arising During Period, Net of Tax	0
Current period change, net of tax Net Unrealized Gain/(Loss) on Investments	1	0	(20)
Current period change, net of tax Benefit Obligations	(2)	(9)	15
Current period change, net of tax Foreign Currency Translation	1	0	1
Current period change, net of tax AccumulatedOther Comprehensive Loss	$ 0