Property and Equipment, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 64,355	$ 59,356
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(4,845)	(3,550)
Property, Plant and Equipment, Net	59,510	55,806
Interest Costs Capitalized	34	30	$ 29
Property and Equipment under Capital Lease [Member]
Property, Plant and Equipment [Line Items]
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(362)	(374)
Capital Leased Asset, Net	814	854
Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	6,037	5,983
Track Structure [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	21,200	19,562
Other Roadway [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	24,767	23,026
Locomotives [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	7,794	6,621
Freight Cars and Other Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	2,629	2,350
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	897	522
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 1,031	$ 1,292
Minimum [Member] | Track Structure [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	15 years
Minimum [Member] | Other Roadway [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	7 years
Minimum [Member] | Locomotives [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	7 years
Minimum [Member] | Freight Cars and Other Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	8 years
Minimum [Member] | Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	6 years
Maximum [Member] | Track Structure [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	50 years
Maximum [Member] | Other Roadway [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	100 years
Maximum [Member] | Locomotives [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	35 years
Maximum [Member] | Freight Cars and Other Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	40 years
Maximum [Member] | Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	9 years