Nature of Operations and Significant Accounting Policies - Narrative (Details) mi in Thousands, carload in Thousands, shares in Millions	1 Months Ended		3 Months Ended								12 Months Ended
	Nov. 30, 2015 employee	Oct. 31, 2015 employee	Dec. 30, 2016 USD ($) employee railroad port_terminal state terminal mi	Sep. 23, 2016 USD ($)	Jun. 24, 2016 USD ($)	Mar. 25, 2016 USD ($)	Dec. 25, 2015 USD ($)	Sep. 25, 2015 USD ($)	Jun. 26, 2015 USD ($)	Mar. 27, 2015 USD ($)	Dec. 30, 2016 USD ($) employee railroad carload port_terminal state terminal mi shares	Dec. 25, 2015 USD ($) shares	Dec. 26, 2014 USD ($) employee shares	Apr. 30, 2015 USD ($)
Revenue from External Customer [Line Items]
Number of employees | employee			27,000								27,000
Number of union employees | employee											22,000
Number of rail route miles | mi			21								21
Rail network states number | state			23								23
Number of short-line and regional railroads served | railroad			240								240
Revenue			$ 3,037,000,000	$ 2,710,000,000	$ 2,704,000,000	$ 2,618,000,000	$ 2,781,000,000	$ 2,939,000,000	$ 3,064,000,000	$ 3,027,000,000	$ 11,069,000,000	$ 11,811,000,000	$ 12,669,000,000
Cost method, maximum percentage											20.00%
Cash equivalents maximum maturity period (in months)											3 months
Short-term investments, minimum maturity period											3 months
Short-term investments, maximum maturity period											1 year
Allowance for doubtful accounts			33,000,000				37,000,000				$ 33,000,000	37,000,000
Goodwill			$ 63,000,000				63,000,000				63,000,000	63,000,000
Share repurchase program														$ 2,000,000,000
Shares acquired, repurchase amount											$ 1,056,000,000	$ 804,000,000	$ 517,000,000
Stock repurchased (in shares) | shares											38	26	17
Separation costs												$ 51,000,000	$ 39,000,000
Union agreements
Revenue from External Customer [Line Items]
Number of positions reduced | employee	300
Facility closures
Revenue from External Customer [Line Items]
Number of positions reduced | employee		500
Management streamlining
Revenue from External Customer [Line Items]
Number of positions reduced | employee													300
Minimum
Revenue from External Customer [Line Items]
Number of ocean, river and lake ports serviced (more than) | port_terminal			70								70
Merchandise business
Revenue from External Customer [Line Items]
Number of carloads | carload											2,800
Percentage of total revenue											64.00%
Percentage of total volume											43.00%
Coal business
Revenue from External Customer [Line Items]
Number of carloads | carload											838
Percentage of total revenue											17.00%
Percentage of total volume											13.00%
Intermodal business
Revenue from External Customer [Line Items]
Percentage of total revenue											16.00%
Percentage of total volume											44.00%
Number of terminals (more than) | terminal			50								50
Other business
Revenue from External Customer [Line Items]
Percentage of total revenue											3.00%
New Accounting Pronouncement, Early Adoption, Effect
Revenue from External Customer [Line Items]
Deferred tax assets, net, current							126,000,000					126,000,000
Deferred tax liabilities, net, current							$ 126,000,000					$ 126,000,000