Property and Equipment, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 67,380	$ 64,355
Accumulated Depreciation and Amortization	6,130	4,845
Property and Equipment, Net	61,250	59,510
Interest Costs Capitalized	26	34	$ 30
Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	6,063	6,037
Track Structure [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	22,287	21,200
Other Roadway [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	25,990	24,767
Locomotives [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	8,338	7,794
Freight Cars and Other Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	2,755	2,629
Computer Hardware, Software and Other [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	982	897
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	965	1,031
Property and Equipment under Capital Lease [Member]
Property, Plant and Equipment [Line Items]
Accumulated Depreciation and Amortization	333	362
Capital Leased Asset, Net	$ 738	$ 814
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 Hardware, Software and Other [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 Hardware, Software and Other [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	9 years