Properties (Detail of Net Properties) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 30, 2011 years		Dec. 31, 2010 years
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 33,704		$ 32,065
Accumulated Depreciation	(8,730)		(8,266)
Properties - Net (Note 6)	24,974		23,799
Percentage of Assets Depreciated Under Group Life Method	85.00%		85.00%
Road - Total [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	22,379		20,906
Accumulated Depreciation	(4,889)		(4,317)
Properties - Net (Note 6)	17,490		16,589
Estimated Useful Life, Minimum (in years)	6		6
Estimated Useful Life, Maximum (in years)	80		80
Road - Rail and Other Track Material [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	5,949		5,568
Accumulated Depreciation	(1,021)		(937)
Properties - Net (Note 6)	4,928		4,631
Annual Depreciation Rate (in hundredths)	2.70%	[1]	2.70%	[1]
Depreciation Method	Group Life		Group Life
Road - Ties [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	4,126		3,896
Accumulated Depreciation	(868)		(807)
Properties - Net (Note 6)	3,258		3,089
Annual Depreciation Rate (in hundredths)	3.70%	[1]	3.70%	[1]
Depreciation Method	Group Life		Group Life
Road - Grading [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	2,379		2,368
Accumulated Depreciation	(382)		(348)
Properties - Net (Note 6)	1,997		2,020
Annual Depreciation Rate (in hundredths)	1.30%	[1]	1.30%	[1]
Depreciation Method	Group Life		Group Life
Estimated Useful Life, Maximum (in years)	80
Road - Ballast [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	2,446		2,372
Accumulated Depreciation	(610)		(605)
Properties - Net (Note 6)	1,836		1,767
Annual Depreciation Rate (in hundredths)	2.50%	[1]	2.50%	[1]
Depreciation Method	Group Life		Group Life
Road - Bridges, Trestles, and Culverts [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	1,887		1,815
Accumulated Depreciation	(195)		(170)
Properties - Net (Note 6)	1,692		1,645
Annual Depreciation Rate (in hundredths)	1.40%	[1]	1.40%	[1]
Depreciation Method	Group Life		Group Life
Road - Signals and Interlockers [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	1,680		1,610
Accumulated Depreciation	(198)		(183)
Properties - Net (Note 6)	1,482		1,427
Annual Depreciation Rate (in hundredths)	3.30%	[1]	3.30%	[1]
Depreciation Method	Group Life		Group Life
Road - Buildings [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	874		750
Accumulated Depreciation	(342)		(253)
Properties - Net (Note 6)	532		497
Annual Depreciation Rate (in hundredths)	2.50%	[1]	2.50%	[1]
Depreciation Method	Group Life		Group Life
Road - Other [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	3,038		2,527
Accumulated Depreciation	(1,273)		(1,014)
Properties - Net (Note 6)	1,765		1,513
Annual Depreciation Rate (in hundredths)	3.00%	[1]	3.00%	[1]
Depreciation Method	Group Life		Group Life
Estimated Useful Life, Minimum (in years)	6
Total Equipment [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	8,621		7,443
Accumulated Depreciation	(3,801)		(3,147)
Properties - Net (Note 6)	4,820		4,296
Estimated Useful Life, Minimum (in years)	5		5
Estimated Useful Life, Maximum (in years)	35		35
Equipment - Locomotive [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	4,455		4,354
Accumulated Depreciation	(1,960)		(1,852)
Properties - Net (Note 6)	2,495		2,502
Annual Depreciation Rate (in hundredths)	3.50%	[1]	3.50%	[1]
Depreciation Method	Group Life		Group Life
Equipment - Freight Cars [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	2,821		2,653
Accumulated Depreciation	(1,095)		(1,096)
Properties - Net (Note 6)	1,726		1,557
Annual Depreciation Rate (in hundredths)	3.50%	[1]	3.50%	[1]
Depreciation Method	Group Life		Group Life
Equipment - Work Equipment and Other [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	1,345		436
Accumulated Depreciation	(746)		(199)
Properties - Net (Note 6)	599		237
Annual Depreciation Rate (in hundredths)	7.30%	[1]	7.30%	[1]
Depreciation Method	Group Life		Group Life
Estimated Useful Life, Maximum (in years)	35
Land [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	1,832		1,875
Properties - Net (Note 6)	1,832		1,875
Construction in Progress [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	728		529
Properties - Net (Note 6)	728		529
Other properties [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	144		1,312
Accumulated Depreciation	(40)		(802)
Properties - Net (Note 6)	$ 104		$ 510
Depreciation Method	Straight Line		Straight Line
Estimated Useful Life, Minimum (in years)	4		4
Estimated Useful Life, Maximum (in years)	30		30

[1] Composite depreciation rates, which are used in group life depreciation, apply to railroad assets which account for more than 85% of total properties. All other property is depreciated on a straight line basis over the asset’s useful life.