XML 12 R39.htm IDEA: XBRL DOCUMENT v2.4.1.9
Fair Value Measurements Narrative (Details) (Level 2, USD $)
In Billions, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Level 2
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, fair value $ 4.3us-gaap_LongTermDebtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
$ 3.8us-gaap_LongTermDebtFairValue
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member