Properties - Schedule of Net Properties (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 30, 2016	Dec. 25, 2015
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 43,227	$ 41,574
Accumulated Depreciation	(12,077)	(11,400)
Properties - Net	31,150	30,174
Total Road
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	28,824	27,564
Accumulated Depreciation	(7,324)	(6,758)
Properties - Net	21,500	20,806
Rail and Other Track Material
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	7,326	7,150
Accumulated Depreciation	(1,493)	(1,414)
Properties - Net	$ 5,833	$ 5,736
Annual Depreciation Rate	2.50%	2.50%
Estimated useful life	40 years	40 years
Ties
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 5,368	$ 5,077
Accumulated Depreciation	(1,292)	(1,147)
Properties - Net	$ 4,076	$ 3,930
Annual Depreciation Rate	3.70%	3.70%
Estimated useful life	27 years	27 years
Grading
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 2,600	$ 2,533
Accumulated Depreciation	(514)	(479)
Properties - Net	$ 2,086	$ 2,054
Annual Depreciation Rate	1.40%	1.40%
Estimated useful life	90 years	90 years
Ballast
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 2,897	$ 2,793
Accumulated Depreciation	(860)	(802)
Properties - Net	$ 2,037	$ 1,991
Annual Depreciation Rate	2.70%	2.70%
Estimated useful life	37 years	37 years
Bridges, Trestles, and Culverts
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 2,306	$ 2,238
Accumulated Depreciation	(317)	(283)
Properties - Net	$ 1,989	$ 1,955
Annual Depreciation Rate	1.60%	1.60%
Estimated useful life	70 years	70 years
Signals and Interlockers
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 2,523	$ 2,315
Accumulated Depreciation	(496)	(416)
Properties - Net	$ 2,027	$ 1,899
Annual Depreciation Rate	4.00%	4.00%
Estimated useful life	25 years	25 years
Buildings
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 1,238	$ 1,152
Accumulated Depreciation	(447)	(424)
Properties - Net	$ 791	$ 728
Annual Depreciation Rate	2.50%	2.50%
Estimated useful life	40 years	40 years
Other
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 4,566	$ 4,306
Accumulated Depreciation	(1,905)	(1,793)
Properties - Net	$ 2,661	$ 2,513
Annual Depreciation Rate	4.20%	4.20%
Estimated useful life	24 years	24 years
Total Equipment
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 11,604	$ 11,108
Accumulated Depreciation	(4,740)	(4,633)
Properties - Net	6,864	6,475
Locomotive
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	6,110	5,673
Accumulated Depreciation	(2,504)	(2,461)
Properties - Net	$ 3,606	$ 3,212
Annual Depreciation Rate	3.50%	3.60%
Estimated useful life	29 years	28 years
Freight Cars
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 3,386	$ 3,362
Accumulated Depreciation	(1,046)	(1,018)
Properties - Net	$ 2,340	$ 2,344
Annual Depreciation Rate	2.90%	3.20%
Estimated useful life	35 years	31 years
Work Equipment and Other
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 2,108	$ 2,073
Accumulated Depreciation	(1,190)	(1,154)
Properties - Net	$ 918	$ 919
Annual Depreciation Rate	7.40%	7.10%
Estimated useful life	14 years	13 years
Land
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 1,833	$ 1,858
Properties - Net	1,833	1,858
Construction In Progress
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	913	1,003
Properties - Net	913	1,003
Other
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	53	41
Accumulated Depreciation	(13)	(9)
Properties - Net	$ 40	$ 32
Estimated useful life	32 years	32 years
Minimum | Other
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life	8 years
Maximum | Grading
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life	90 years
Maximum | Work Equipment and Other
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life	40 years