Summarized Consolidating Financial Data - Consolidating Income Statements (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Consolidated Income Statement
Revenue	$ 2,876	$ 2,869
Expense	1,832	2,100
Operating Income	1,044	769
Equity in Earnings of Subsidiaries	0	0
Interest (Expense) / Benefit	(149)	(137)
Other Income / (Expense) - Net	17	(50)
Earnings Before Income Taxes	912	582
Income Tax Benefit / (Expense)	(217)	(220)
Net Earnings	695	362
Total Comprehensive Earnings	596	368
Eliminations and Other
Consolidated Income Statement
Revenue	19	18
Expense	(33)	(80)
Operating Income	52	98
Equity in Earnings of Subsidiaries	(758)	(422)
Interest (Expense) / Benefit	24	15
Other Income / (Expense) - Net	(10)	(64)
Earnings Before Income Taxes	(692)	(373)
Income Tax Benefit / (Expense)	(12)	(16)
Net Earnings	(704)	(389)
Total Comprehensive Earnings	(700)	(387)
CSX Corporation
Consolidated Income Statement
Revenue	0	0
Expense	(78)	(48)
Operating Income	78	48
Equity in Earnings of Subsidiaries	758	422
Interest (Expense) / Benefit	(164)	(142)
Other Income / (Expense) - Net	4	3
Earnings Before Income Taxes	676	331
Income Tax Benefit / (Expense)	19	31
Net Earnings	695	362
Total Comprehensive Earnings	596	368
CSX Transportation
Consolidated Income Statement
Revenue	2,857	2,851
Expense	1,943	2,228
Operating Income	914	623
Equity in Earnings of Subsidiaries	0	0
Interest (Expense) / Benefit	(9)	(10)
Other Income / (Expense) - Net	23	11
Earnings Before Income Taxes	928	624
Income Tax Benefit / (Expense)	(224)	(235)
Net Earnings	704	389
Total Comprehensive Earnings	$ 700	$ 387