Commitments and Contingencies - Personal Injury (Details) (USD $) In Millions, unless otherwise specified					3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2013 Unasserted Claim	Mar. 31, 2013 Personal Injury	Mar. 31, 2012 Personal Injury	Mar. 31, 2013 Commercial Paper, Bank Time Deposits, and Money Market Funds BNSF Insurance Company	Dec. 31, 2012 Commercial Paper, Bank Time Deposits, and Money Market Funds BNSF Insurance Company	Mar. 31, 2013 Current Liabilities [Member]
Asbestos and Personal Injury [Abstract]
Percent of future unasserted asbestos claims to be filed within the next ten years					60.00%
Percent of future unasserted asbestos claims to be filed within the next fifteen years					80.00%
Percent of future unasserted asbestos claims to be filed within the next twenty-five years					95.00%
Length in years for 60 percent of future unasserted asbestos claims to be filed					10 years
Length in years for 80 percent of future unasserted asbestos claims to be filed					15 years
Length in years for 95 percent of future unasserted claims to be filed					25 years
Accrued obligations for asbestos and other personal injury matters, current liabilities										$ 95
Future costs to settle personal injury claims, minimum						405
Future costs to settle personal injury claims, maximum						520
Loss Contingency Accrual [Roll Forward]
Beginning balance						462	540
Accruals						26	23
Payments						(35)	(57)
Ending balance						453	506
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 2,385	$ 1,794	$ 2,276	$ 1,960				$ 480	$ 485