Commitments and Contingencies - Personal Injury (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2012 Unasserted Claim	Sep. 30, 2012 Personal Injury	Sep. 30, 2011 Personal Injury	Sep. 30, 2012 Personal Injury	Sep. 30, 2011 Personal Injury	Sep. 30, 2012 Commercial Paper, Bank Time Deposits, and Money Market Funds BNSF Insurance Company	Dec. 31, 2011 Commercial Paper, Bank Time Deposits, and Money Market Funds BNSF Insurance Company	Sep. 30, 2012 Current Liabilities [Member]
Asbestos and Personal Injury [Abstract]
Reduction in expense due to settlements of personal injury liabiltiies	$ 15
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												105
Future costs to settle personal injury claims, minimum						425		425
Future costs to settle personal injury claims, maximum						540		540
Loss Contingency Accrual [Roll Forward]
Beginning balance						511	561	540	575
Accruals						(5)	19	45	62
Payments						(33)	(23)	(112)	(80)
Ending balance						473	557	473	557
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 2,259	$ 1,960	$ 2,059	$ 2,087						$ 477	$ 500