XML 129 R102.htm IDEA: XBRL DOCUMENT v2.4.1.9
Income Taxes Unrecognized Tax Benefits Narrative (Details) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2012
Dec. 31, 2013
Dec. 31, 2011
Income Tax Contingency        
Unrecognized tax benefits $ 21us-gaap_UnrecognizedTaxBenefits $ 30us-gaap_UnrecognizedTaxBenefits $ 28us-gaap_UnrecognizedTaxBenefits $ 31us-gaap_UnrecognizedTaxBenefits
Unrecognized tax benefits recognized as liabilities 4tso_UnrecognizedTaxBenefitsRecognizedAsLiabilities   4tso_UnrecognizedTaxBenefitsRecognizedAsLiabilities  
Unrecognized tax benefits that would impact effective tax rate 15us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate   17us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate  
Possible decrease in unrecognized tax benefits in the next twelve months 8us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleEstimatedRangeOfChangeUpperBound      
Accrued interest and penalties 1us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued   1us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued  
Unrecognized tax benefits, period change $ 0us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease $ 3us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease    
Internal Revenue Service (IRS)        
Income Tax Contingency        
Open tax year 2006      
State Taxing Authorities        
Income Tax Contingency        
Open tax year 2006