1.0.0.3 true Consolidated Statement of Equity (Parenthetical) (Unaudited) (USD $) In Millions, except Per Share data false 1 $ false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDEPS Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 2 Dividends declared per share 2 us-gaap_CommonStockDividendsPerShareDeclared us-gaap true na duration decimal No definition available. false false false false false false false false true 1 true true 0.8 0.8 false false No definition available. No authoritative reference available. false 3 Restricted stock activity, tax expense 2 bni_RestrictedStockActivityAndRelatedTaxBenefitExpense bni false na duration monetary The net tax benefit (expense) resulting from restricted stock activity during the period as a result of the share-based... false false false false false false false false false 1 true true 3000000 3 false false The net tax benefit (expense) resulting from restricted stock activity during the period as a result of the share-based compensation plan. No authoritative reference available. false 4 Exercise of stock options, tax benefit 2 bni_ExerciseOfStockOptionsAndRelatedTaxBenefit bni false na duration monetary The net tax benefit resulting from the issuance of stock during the period as a result of the exercise of stock options. false false false false false false false false false 1 false true 6000000 6 false false The net tax benefit resulting from the issuance of stock during the period as a result of the exercise of stock options. No authoritative reference available. false 5 Change in unrecognized prior service credit and actuarial losses, tax expense 2 bni_ChangeInUnrecognizedPriorServiceCreditAndActuarialLossesTaxBenefitExpense bni false na duration monetary The net tax benefit (expense) resulting from the adjustment out of other comprehensive income for prior service costs and... false false false false false false false false false 1 false true 4000000 4 false false The net tax benefit (expense) resulting from the adjustment out of other comprehensive income for prior service costs and actual losses recognized as a component of net period benefit cost during the period. No authoritative reference available. false 6 Fuel/interest hedge mark-to-market and other items, tax expense 2 bni_FuelInterestHedgeMarkToMarketTaxBenefit bni false na duration monetary The net tax benefit (expense) resulting from the change in accumulated gains and losses from derivative instrument designated... false false false false false false false false false 1 false true 147000000 147 false false The 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 authoritative reference available. false 7 Recognized loss on derivative instruments - discontinued hedges, tax benefit 2 bni_RecognizedLossOnDerivativeInstrumentsDiscontinuedHedgesTaxBenefit bni false na duration monetary The tax effect of discontinuance of hedge accounting on certain derivative instruments included in accumulated comprehensive... false false false false false false false false false 1 false true 16000000 16 false false The tax effect of discontinuance of hedge accounting on certain derivative instruments included in accumulated comprehensive income that was recognized in net income during the period. No authoritative reference available. false 8 Common Stock and Paid-in Capital 0 na true na na na No definition available. false true false false false false false false false 1 false false 0 0 false false No definition available. No authoritative reference available. false 10 Restricted stock activity, tax expense 2 bni_RestrictedStockActivityAndRelatedTaxBenefitExpense bni false na duration monetary The net tax benefit (expense) resulting from restricted stock activity during the period as a result of the share-based... false false false false false false false false false 1 false true 3000000 3 false false The net tax benefit (expense) resulting from restricted stock activity during the period as a result of the share-based compensation plan. No authoritative reference available. false 11 Exercise of stock options, tax benefit 2 bni_ExerciseOfStockOptionsAndRelatedTaxBenefit bni false na duration monetary The net tax benefit resulting from the issuance of stock during the period as a result of the exercise of stock options. false false false false false false false false false 1 false true 6000000 6 false false The net tax benefit resulting from the issuance of stock during the period as a result of the exercise of stock options. No authoritative reference available. false 15 Treasury Stock 0 na true na na na No definition available. false true false false false false false false false 1 false false 0 0 false false No definition available. No authoritative reference available. false 17 Restricted stock activity, tax expense 2 bni_RestrictedStockActivityAndRelatedTaxBenefitExpense bni false na duration monetary The net tax benefit (expense) resulting from restricted stock activity during the period as a result of the share-based... false false false false false false false false false 1 false true 3000000 3 false false The net tax benefit (expense) resulting from restricted stock activity during the period as a result of the share-based compensation plan. No authoritative reference available. false 18 Exercise of stock options, tax benefit 2 bni_ExerciseOfStockOptionsAndRelatedTaxBenefit bni false na duration monetary The net tax benefit resulting from the issuance of stock during the period as a result of the exercise of stock options. false false false false false false false false false 1 false true 6000000 6 false false The net tax benefit resulting from the issuance of stock during the period as a result of the exercise of stock options. No authoritative reference available. false 22 Retained Earnings 0 na true na na na No definition available. false true false false false false false false false 1 false false 0 0 false false No definition available. No authoritative reference available. false 23 Dividends declared per share 2 us-gaap_CommonStockDividendsPerShareDeclared us-gaap true na duration decimal No definition available. false false false false false false false false true 1 true true 0.8 0.8 false false No definition available. No authoritative reference available. false 29 Accumulated Other Comprehensive Loss 0 na true na na na No definition available. false true false false false false false false false 1 false false 0 0 false false No definition available. No authoritative reference available. false 33 Change in unrecognized prior service credit and actuarial losses, tax expense 2 bni_ChangeInUnrecognizedPriorServiceCreditAndActuarialLossesTaxBenefitExpense bni false na duration monetary The net tax benefit (expense) resulting from the adjustment out of other comprehensive income for prior service costs and... false false false false false false false false false 1 false true 4000000 4 false false The net tax benefit (expense) resulting from the adjustment out of other comprehensive income for prior service costs and actual losses recognized as a component of net period benefit cost during the period. No authoritative reference available. false 34 Fuel/interest hedge mark-to-market and other items, tax expense 2 bni_FuelInterestHedgeMarkToMarketTaxBenefit bni false na duration monetary The net tax benefit (expense) resulting from the change in accumulated gains and losses from derivative instrument designated... false false false false false false false false false 1 false true 147000000 147 false false The 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 authoritative reference available. false 35 Recognized loss on derivative instruments - discontinued hedges, tax benefit 2 bni_RecognizedLossOnDerivativeInstrumentsDiscontinuedHedgesTaxBenefit bni false na duration monetary The tax effect of discontinuance of hedge accounting on certain derivative instruments included in accumulated comprehensive... false false false false false false false false false 1 true true 16000000 16 false false The tax effect of discontinuance of hedge accounting on certain derivative instruments included in accumulated comprehensive income that was recognized in net income during the period. No authoritative reference available. false false 1 18 false Millions UnKnown Hundreds false true