v2.4.1.9
Amortization of Capital Leases (Detail) (USD $)
In Millions, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Capital Leased Assets [Line Items]    
Capital leases $ 319us-gaap_CapitalLeasedAssetsGross $ 353us-gaap_CapitalLeasedAssetsGross
Less accumulated amortization 171us-gaap_CapitalLeasesLesseeBalanceSheetAssetsByMajorClassAccumulatedDeprecation 188us-gaap_CapitalLeasesLesseeBalanceSheetAssetsByMajorClassAccumulatedDeprecation
Total $ 148us-gaap_CapitalLeasesBalanceSheetAssetsByMajorClassNet $ 165us-gaap_CapitalLeasesBalanceSheetAssetsByMajorClassNet