Information Systems and Processes XBRL Formulae in a Nutshell Víctor Morilla VIII European Banking Supervisors XBRL Workshop Amsterdam November 2007

INFORMATION SYSTEMS AND PROCESSES 2 Introduction XBRL 2.1 provides different types of validation for instance documents: –Basic XBRL validation –XML Schema validation –Calculation linkbase –XBRL Dimensions These validations are not enough in most cases: –Basic arithmetic operations: product, division, … –Arithmetic comparisons: item A must be equal to item B, … –Checks for the presence of elements Derivation of new facts from existing ones is not possible XBRL Formulae is meant to fill the gap

INFORMATION SYSTEMS AND PROCESSES 3 Why a XBRL Formulae specification? Requirements –Declarative language –Intuitive –Maintainable –Extensible –Reusing existing standards Business oriented

INFORMATION SYSTEMS AND PROCESSES 4 Brief history June 2005: first public working draft of Formulae Requirements November 2006: the Formulae WG is constituted with the following purpose: –Documenting complex functional relationships between concepts at a definitional level –Deriving new XBRL facts from available XBRL information –Reporting messages describing the outcomes of formula execution –Reporting consistency of formulae with the available XBRL information January 2007: first Formula PWD Specification published February 2007: public survey on first PWD July 2007: second PWD adds –Implicit filter –Dimensional filters

INFORMATION SYSTEMS AND PROCESSES 5 Parts of the XBRL Formulae specification Formulae Variables Concept filter Entity filter Scenario/segment filter Tuple filter Period filter Unit filter Dimensions filter Generic labels Generic references XBRL Functions XBRL Functions Registry W3C XPath 2.0

INFORMATION SYSTEMS AND PROCESSES 6 XBRL Formulae step by step (x 1, x 2, x 3, …, x n ) y y = (a + b) * c Arithmetic expression

INFORMATION SYSTEMS AND PROCESSES 7 XBRL Formulae expression language: XPath 2.0 W3C Recommendation (since January 2007) Already supported by several tools XPath 2.0 is an expression language: Arithmetic expressions Comparison expressions Logical expressions Conditional expressions … Defines a set of standard operators and functions: +, -, *, div, mod, =, !=,, and, or, … fn:abs, fn:ceiling, fn:floor, fn:concat, fn:upper-case, … … Can call external functions Proprietary XBRL Functions Specification: a set of predefined accessor functions XBRL Function Registry

INFORMATION SYSTEMS AND PROCESSES 8 XBRL Formulae step by step (x 1, x 2, x 3, …, x n ) y y = (a + b) * c a concept: CurrentAssets period: January 2005 entity: Dutch Bank b concept: LongTermAssets period: January 2005 entity: Dutch Bank c concept: RiskFactor period: January 2005 entity: Dutch Bank y concept: WeightedRiskAssets period: January 2005 entity: Dutch Bank Variables and filters specification Formula specification

INFORMATION SYSTEMS AND PROCESSES 9 Variables and filters A variable is defined by a set of conditions: filters Concept filter Entity filter Scenario/segment filter Tuple filter Period filter Unit filter Dimensions filter Value filter A filter can be relative to another variable b: period(a) - 1 A variable can be defined as a sequence y = sum(a)

INFORMATION SYSTEMS AND PROCESSES 10 XBRL Formulae step by step (x 1, x 2, x 3, …, x n ) y y = (a + b) * c a concept: CurrentAssets period: January 2005 entity: Dutch Bank b concept: LongTermAssets period: January 2005 entity: Dutch Bank c concept: RiskFactor period: January 2005 entity: Dutch Bank y concept: WeightedRiskAssets period: January 2005 entity: Dutch Bank

INFORMATION SYSTEMS AND PROCESSES 11 Example instance document EntityPeriodCurrentAssetsLongTermAssetsRiskFactor Dutch BankJanuary March May ACME CorpJanuary March May ……………

INFORMATION SYSTEMS AND PROCESSES 12 Example formula evaluation a (CurrentAssets)b (LongTermAssets)c (RiskFactor) Jan 2005 / Dutch Bank: Jan 2005 / Dutch Bank: Jan 2005 / Dutch Bank: 0.25 Jan 2005 / Dutch Bank: Jan 2005 / Dutch Bank: March 2005 / Dutch Bank: 0.33 Jan 2005 / Dutch Bank: Jan 2005 / Dutch Bank: May 2005 / Dutch Bank: 0.35 Jan 2005 / Dutch Bank: March 2005 / Dutch Bank: Jan 2005 / Dutch Bank: 0.25 Jan 2005 / Dutch Bank: March 2005 / Dutch Bank: March 2005 / Dutch Bank: 0.33 Jan 2005 / Dutch Bank: March 2005 / Dutch Bank: May 2005 / Dutch Bank: 0.35 Jan 2005 / Dutch Bank: May 2005 / Dutch Bank: Jan 2005 / Dutch Bank: 0.25 Jan 2005 / Dutch Bank: May 2005 / Dutch Bank: March 2005 / Dutch Bank: 0.33 Jan 2005 / Dutch Bank: May 2005 / Dutch Bank: May 2005 / Dutch Bank: 0.35 March 2005 / Dutch Bank: Jan 2005 / Dutch Bank: Jan 2005 / Dutch Bank: 0.25 March 2005 / Dutch Bank: Jan 2005 / Dutch Bank: March 2005 / Dutch Bank: 0.33 March 2005 / Dutch Bank: Jan 2005 / Dutch Bank: May 2005 / Dutch Bank: 0.35 ………

INFORMATION SYSTEMS AND PROCESSES 13 Variable implicit filter Implicit filter discards unwanted combinations All not explicitly filtered aspects of variables in a formula must match PeriodEntitya (CurrentAssets)b (LongTermAssets)c (RiskFactor) Jan 2005Dutch Bank March 2005Dutch Bank May 2005Dutch Bank Jan 2005Acme Corp March 2005Acme Corp May 2005Acme Corp …… ………

INFORMATION SYSTEMS AND PROCESSES 14 Validations The validation specification defines different kinds of validations: Assertions CurrentAssets + LongTermAssets > 0 Assets must be equal to Liabilities + Equities Existence of facts TotalIncomes is reported Formulae consistency check The calculated value of TotalAssets given the formulae: TotalAssets = CurrentAssets + LongTermAssets, must be consistent with the value reported in an instance document To be included in the next working draft

INFORMATION SYSTEMS AND PROCESSES 15 Others Documentation of formulae: Generic labels Generic references Future developments Formulae chaining Template documents

INFORMATION SYSTEMS AND PROCESSES 16 Summary Variables Filters Formulae XPath 2.0 XPath Std Functions XBRL Functions XBRL Function Registry Validation Generic labels and references Other usage patterns Other specs

INFORMATION SYSTEMS AND PROCESSES 17 Next steps Release of the next public working draft Development of the conformance suite Release of the first candidate recommendation

INFORMATION SYSTEMS AND PROCESSES 18 How can I contribute? -Use cases for the conformance suite: -Taxonomy files -Input instance documents -Expected result -Review of the specification -Transmit your interest in XBRL Formulae to your software vendors Ask not what XBRL can do for you Ask what you can do for XBRL

Information Systems and Processes THANKS FOR YOUR ATTENTION Víctor Morilla