2.4.0.81002501 - Statement - Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical)truefalseIn Millions, unless otherwise specifiedfalse1false USDfalsefalse$D2013Q2http://www.sec.gov/CIK0000934612duration2013-04-01T00:00:002013-06-30T00:00:00usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$2false USDfalsefalse$D2012Q2http://www.sec.gov/CIK0000934612duration2012-04-01T00:00:002012-06-30T00:00:00usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$3false USDfalsefalse$D2013Q2YTDhttp://www.sec.gov/CIK0000934612duration2013-01-01T00:00:002013-06-30T00:00:00usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$4false USDfalsefalse$D2012Q2YTDhttp://www.sec.gov/CIK0000934612duration2012-01-01T00:00:002012-06-30T00:00:00usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$1false 4bni_ChangeInUnrecognizedPriorServiceCreditAndActuarialLossesTaxBenefitExpensebni_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse20000002USD$falsetruefalse2truefalsefalse00USD$falsetruefalse3truefalsefalse40000004USD$falsetruefalse4truefalsefalse20000002USD$falsetruefalsexbrli:monetaryItemTypemonetaryChange In Unrecognized Prior Service Credit And Actuarial Losses Tax Benefit (Expense)No definition available.false2Change in amortization of accumulated actuarial losses, net of tax expense2false 4bni_FuelInterestHedgeMarkToMarketTaxBenefitExpensebni_falsedebitdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse00USD$falsetruefalse2truefalsefalse-2000000-2USD$falsetruefalse3truefalsefalse00USD$falsetruefalse4truefalsefalse-7000000-7USD$falsetruefalsexbrli:monetaryItemTypemonetaryThe net tax (benefit) expense resulting from the change in accumulated gains and losses from derivative instrument designated and qualifying as the effective portion of cash flow hedges, net of tax effect.No definition available.false2Change in fuel hedge mark-to-market, net of tax expense/(benefit)falseConsolidated Statements of Comprehensive Income (Unaudited) (Parenthetical) (USD $)MillionsUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.bnsf.com/role/ConsolidatedStatementsOfComprehensiveIncomeUnauditedParenthetical42