Accounts Payable and Other Current Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Accounts Payable and Other Current Liablities [Line Items]
Compensation and benefits payable	$ 776	$ 789
Property and income tax liabilities	337	330
Capital expenditure estimated liabilities	317	195
Accounts payable	292	344
Accrued interest	286	265
Customer incentives	135	151
Casualty and environmental liabilities	135	140
Rents and leases	111	158
Other	855	1,063
Total	$ 3,244	$ 3,435