CONSOLIDATED INCOME STATEMENTS - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 30, 2016	Dec. 25, 2015
Income Statement [Abstract]
Revenue	$ 11,408	$ 11,069	$ 11,811
Expense
Labor and Fringe	2,914	3,159	3,290
Materials, Supplies and Other	2,113	2,092	2,356
Depreciation	1,315	1,301	1,208
Fuel	864	713	957
Equipment and Other Rents	429	465	456
Restructuring Charges (Note 1)	325	0	0
Equity Earnings of Affiliates	(219)	(50)	(40)
Total Expense	7,741	7,680	8,227
Operating Income	3,667	3,389	3,584
Interest Expense	(546)	(579)	(544)
Debt Repurchase Expense	0	(115)	0
Other Income (Expense) - Net (Note 10)	21	46	98
Earnings Before Income Taxes	3,142	2,741	3,138
Income Tax Benefit (Expense) (Note 11)	2,329	(1,027)	(1,170)
Net Earnings	$ 5,471	$ 1,714	$ 1,968
Net Earnings Per Share
Basic (in dollars per share)	$ 6.01	$ 1.81	$ 2.00
Assuming Dilution (in dollars per share)	$ 5.99	$ 1.81	$ 2.00
Average Common Shares Outstanding
Basic (shares)	911	947	983
Assuming Dilution (shares)	914	948	984
Cash Dividends Paid Per Common Share	$ 0.78	$ 0.72	$ 0.70