The total contractually required rental payments on leases in which the structure of the leases contain variable interest entities.

Name:	unp_FutureMinimumLeasePaymentsVies
Namespace Prefix:	unp
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Name:	unp_VariableInterestEntitiesDetailsAbstract
Namespace Prefix:	unp
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration