Accounting Policies and Interim Results (Details) - Burlington Northern Santa Fe Corporation [Member]	Sep. 30, 2019	Feb. 12, 2010
Business Acquisition [Line Items]
Acquired remaining outstanding shares, percentage		100.00%
Holders of membership interests	1

In a business combination achieved in stages, this element represents the percentage aquired of the remaining equity interest in the acquiree not already owned.

No definition available.

Name:	bni_BusinessCombinationStepAcquisitionRemainingEquityInterestAcquiredPercentage
Namespace Prefix:	bni_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant