Nil Values on Typed Axis

Rule function

This rule identifies when a nil value has been used inappropriately on a typed axis. This rule applies to all typed axes used in the filing.
The rule reports an error for every fact that has a nil member associated with it.

Problem solved by the rule

A nil value is often added to a typed dimension to represent the default value. In the case of revenue recognition the FASB requires that the default value is represented without an axis with a nil value. In effect, adding a nil value creates alternative methods to define the same fact value. For this reason nil values on a typed dimension should be avoided.

Scope of the Rule

This rule applies to all US GAAP Taxonomies issued in 2017 and later.

Example rule message

The element us-gaap:RevenueRemainingPerformanceObligation with a value of 3,900,000,000 has been tagged with the axis RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis with a nil value as a member. This element should be reported without using this axis.

The properties of this us-gaap:RevenueRemainingPerformanceObligation fact are:
Period: 2018-03-31
Dimensions: us-gaap:ProductOrServiceAxis=f:ExtendedServiceContractsMember, us-gaap:StatementBusinessSegmentsAxis=f:AutomotiveSegmentMember, us-gaap:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember, us-gaap:RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis=None
Unit: USD

Rule Element Id: 7649
Rule version: 7.0.0

For Developers

The Global Rule Logic document contains general guidelines for implementation of rules.

The rule message template contains text and parametric reference to arguments of the rule operation, using the syntax ${parameter} to indicate that insertion of a parameter’s value is to occur.

Message template

The element {$fact_with_nil_member.concept} with a value of {$fact_with_nil_member} has been tagged with the axis RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis with a nil value as a member. This element should be reported be reported without using this axis.

The properties of this {$fact_with_nil_member.concept} fact are:
Period: {$fact_with_nil_member.period}
Dimensions: {$fact_with_nil_member.dimensions.join(‘, ‘,’=’)}
Unit: {$fact_with_nil_member.unit}

Rule Element Id: 7649
Rule version: {$ruleVersion}

Rule element ID index

The rule element id is used to identify unique elements or combinations of elements tested in the rule.