Summarized Consolidating Financial Data - Consolidating Income Statements (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 23, 2016	Sep. 25, 2015	Sep. 23, 2016	Sep. 25, 2015
Consolidated Income Statement
Revenue	$ 2,710	$ 2,939	$ 8,032	$ 9,030
Expense	1,869	2,006	5,647	6,237
Operating Income	841	933	2,385	2,793
Equity in Earnings of Subsidiaries	0	0	0	0
Interest (Expense) / Benefit	(139)	(136)	(423)	(404)
Other Income / (Expense) - Net	13	2	28	8
Earnings Before Income Taxes	715	799	1,990	2,397
Income Tax Benefit / (Expense)	(260)	(292)	(734)	(895)
Net Earnings	455	507	1,256	1,502
Total Comprehensive Earnings	465	518	1,282	1,523
CSX Corporation
Consolidated Income Statement
Revenue	0	0	0	0
Expense	(63)	(154)	(202)	(448)
Operating Income	63	154	202	448
Equity in Earnings of Subsidiaries	505	496	1,399	1,482
Interest (Expense) / Benefit	(141)	(134)	(425)	(399)
Other Income / (Expense) - Net	0	(1)	1	(4)
Earnings Before Income Taxes	427	515	1,177	1,527
Income Tax Benefit / (Expense)	28	(8)	79	(25)
Net Earnings	455	507	1,256	1,502
Total Comprehensive Earnings	465	518	1,282	1,523
CSX Transportation
Consolidated Income Statement
Revenue	2,691	2,920	7,974	8,972
Expense	1,960	2,182	5,985	6,765
Operating Income	731	738	1,989	2,207
Equity in Earnings of Subsidiaries	1	0	1	0
Interest (Expense) / Benefit	(7)	(8)	(27)	(24)
Other Income / (Expense) - Net	9	5	24	18
Earnings Before Income Taxes	734	735	1,987	2,201
Income Tax Benefit / (Expense)	(268)	(273)	(735)	(824)
Net Earnings	466	462	1,252	1,377
Total Comprehensive Earnings	467	462	1,253	1,374
Eliminations and Other
Consolidated Income Statement
Revenue	19	19	58	58
Expense	(28)	(22)	(136)	(80)
Operating Income	47	41	194	138
Equity in Earnings of Subsidiaries	(506)	(496)	(1,400)	(1,482)
Interest (Expense) / Benefit	9	6	29	19
Other Income / (Expense) - Net	4	(2)	3	(6)
Earnings Before Income Taxes	(446)	(451)	(1,174)	(1,331)
Income Tax Benefit / (Expense)	(20)	(11)	(78)	(46)
Net Earnings	(466)	(462)	(1,252)	(1,377)
Total Comprehensive Earnings	$ (467)	$ (462)	$ (1,253)	$ (1,374)