CONSOLIDATED INCOME STATEMENTS (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 27, 2013	Dec. 28, 2012		Dec. 30, 2011
Income Statement [Abstract]
Revenue	$ 12,026	$ 11,763	[1]	$ 11,795	[1]
Expense
Labor and Fringe	3,138	3,020	[1]	3,073	[1]
Materials, Supplies and Other	2,275	2,156	[1]	2,229	[1]
Fuel	1,656	1,672	[1]	1,668	[1]
Depreciation	1,104	1,059	[1]	976	[1]
Equipment and Other Rents	380	392	[1]	379	[1]
Total Expense	8,553	8,299	[1]	8,325	[1]
Operating Income	3,473	3,464	[1]	3,470	[1]
Interest Expense	(562)	(566)	[1]	(552)	[1]
Other Income - Net	11	73	[1]	22	[1]
Earnings Before Income Taxes	2,922	2,971	[1]	2,940	[1]
Income Tax Expense	(1,058)	(1,108)	[1]	(1,086)	[1]
Net Earnings	$ 1,864	$ 1,863	[1]	$ 1,854	[1]
Net Earnings Per Share, Basic
Earnings Per Share, Basic (dollars per share)	$ 1.83	$ 1.80	[1]	$ 1.71	[1]
Net Earnings Per Common Share, Assuming Dilution
Earnings Per Share, Assuming Dilution (dollars per share)	$ 1.83	$ 1.79	[1]	$ 1.70	[1]
Average Common Shares Outstanding	1,019	1,038	[1]	1,083	[1]
Average Common Shares Outstanding, Assuming Dilution (shares)	1,019	1,040	[1]	1,089	[1]
Cash Dividends Paid Per Common Share	$ 0.59	$ 0.54	[1]	$ 0.45	[1]

[1] See the revision of prior period financial statements in Note 1. Nature of Operations and Significant Accounting Policies.