2.4.0.82402402 - Disclosure - Fuel - Derivative Narrative (Details)truefalsefalse1false falsefalseD2013Q2YTD_us-gaap_ConcentrationRiskByBenchmarkAxis_us-gaap_OperatingExpenseMember_us-gaap_ConcentrationRiskByTypeAxis_bni_CostOfFuelMemberhttp://www.sec.gov/CIK0000934612duration2013-01-01T00:00:002013-06-30T00:00:00numberStandardhttp://www.xbrl.org/2003/instancepurexbrli02false falsefalseD2012Q2YTD_us-gaap_ConcentrationRiskByBenchmarkAxis_us-gaap_OperatingExpenseMember_us-gaap_ConcentrationRiskByTypeAxis_bni_CostOfFuelMemberhttp://www.sec.gov/CIK0000934612duration2012-01-01T00:00:002012-06-30T00:00:00numberStandardhttp://www.xbrl.org/2003/instancepurexbrli01false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse1false truefalseD2013Q2YTD_us-gaap_ConcentrationRiskByBenchmarkAxis_us-gaap_OperatingExpenseMember_us-gaap_ConcentrationRiskByTypeAxis_bni_CostOfFuelMemberhttp://www.sec.gov/CIK0000934612duration2013-01-01T00:00:002013-06-30T00:00:00falsefalseCost of Fuel [Member]us-gaap_ConcentrationRiskByTypeAxisxbrldihttp://xbrl.org/2006/xbrldibni_CostOfFuelMemberus-gaap_ConcentrationRiskByTypeAxisexplicitMemberfalsefalseOperating Expense [Member]us-gaap_ConcentrationRiskByBenchmarkAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_OperatingExpenseMemberus-gaap_ConcentrationRiskByBenchmarkAxisexplicitMembernumberStandardhttp://www.xbrl.org/2003/instancepurexbrli0nanafalse0Cost of Fuel [Member] | Operating Expense [Member]2true 3us-gaap_ConcentrationRiskLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Concentration Risk [Line Items]3false 4us-gaap_ConcentrationRiskPercentage1us-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truetruefalse0.290.29falsefalsefalse2truetruefalse0.300.30falsefalsefalsenum:percentItemTypepureFor an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13537-108611 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6404-108592 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13531-108611 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6351-108592 false0Fuel costs percent of total operating costsfalseFuel - Derivative Narrative (Details) (Cost of Fuel [Member], Operating Expense [Member])UnKnownUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.bnsf.com/role/FuelDerivativeNarrativeDetails23