Contingencies	3 Months Ended
Mar. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Contingencies	Contingencies Life's Good S.T.A.B.L. Hedge Fund In September 2011, three individual investors in Life's Good S.T.A.B.L. Mortgage hedge fund (LG), Marta Klass, Gregory Martin, and Richard Roellig, filed a complaint in the United States District Court for the Eastern District of Pennsylvania against LG, its principal Robert Stinson, and several other parties, including Morningstar, Inc. (the Klass Matter). The plaintiffs claim that Morningstar committed fraud and aided and abetted the other defendants' breach of fiduciary duty through the 5-star rating LG obtained from Morningstar. The plaintiffs seek unspecified damages. Hedge fund managers self-report their performance data to Morningstar. More than a year before the Klass Matter, in June 2010, the SEC filed suit against LG and other entities claiming they were part of a Ponzi scheme operated by Stinson. As a result, LG and the other entities were placed in court-appointed receivership. Morningstar was not part of the SEC suit or receivership. Since that time, the Receiver, as part of his duties, has been investigating whether to assert claims against third parties. Morningstar is aware of 14 lawsuits filed by the Receiver seeking to recover money for the fund. In November 2011, Morningstar filed a motion to dismiss the Klass Matter. On behalf of the entities in receivership, the Receiver filed a motion to stay the proceedings because the Receivership Order does not permit suits against the entities in receivership without court permission. The court granted the Receiver's motion and stayed the Klass Matter. In April 2012, the Receiver filed a complaint against Morningstar, in which the Receiver claims that Morningstar is liable for contribution and aiding and abetting Stinson's breach of fiduciary duty and fraud through the 5-star rating LG obtained from Morningstar. The same day the Receiver filed his complaint, Morningstar sought leave from the court to file a countersuit against Stinson and two of his entities-Keystone State Capital Corporation and LG for, among other things, fraud, misrepresentation, and breach of user agreements. In June 2012, the court denied Morningstar's motion for leave to file suit. The court took no position on the merits of Morningstar's claims, and did not preclude us from renewing our motion to file a complaint at a later time, but deferred to the Receiver's request not to subject the receivership estate to additional litigation at this early point in the receivership. A bench trial related to the Receiver’s claims against Morningstar was held between January 13 and January 28, 2014. At trial, the Receiver claimed that Morningstar is liable under a contribution theory for all or part of a $14.5 million disgorgement judgment that the SEC obtained against the entities and individuals in receivership. Morningstar contested liability and damages at trial and believes it is not liable for any amount. The parties filed post-trial proposed findings of fact and conclusions of law on March 14, 2014. It is not known when the court will issue its decision. We believe the allegations against Morningstar by the Klass plaintiffs and the Receiver have no legal or factual basis, and we plan to continue to vigorously contest the claims. We also intend to refile our affirmative claims against Stinson, Keystone, and LG at a later time consistent with the court's order. We cannot predict the outcome of the proceedings. We have not provided an estimate of loss or range of loss in connection with this matter because no such estimate can reasonably be made. Business Logic Holding Corporation In November 2009, Business Logic Holding Corporation filed a complaint in the Circuit Court of Cook County, Illinois against Ibbotson Associates, Inc., one of our wholly owned subsidiaries, and Morningstar, Inc. relating to Ibbotson's prior commercial relationship with Business Logic. Business Logic is alleging breach of contract and trade secret misappropriation in connection with Ibbotson's development of a proprietary web-service software and user interface that connects plan participant data with the Ibbotson Wealth Forecasting Engine. Ibbotson and Morningstar answered the complaint, and Ibbotson asserted a counterclaim against Business Logic alleging trade secret misappropriation and breach of contract, also seeking damages and injunctive relief. Business Logic filed a motion for summary judgment on its breach of contract claim, which was denied on October 1, 2013. Business Logic also filed a summary motion seeking to dismiss Ibbotson’s counterclaim, which was granted on April 15, 2014. On the same date, the Court granted Ibbotson’s motion for partial summary judgment to dismiss claims on certain enumerated trade secrets, and granted its motion for partial summary judgment on certain damages issues. Business Logic's complaint seeks, among other things, compensatory damages, punitive damages, attorneys' fees, and injunctive relief. With regard to compensatory damages, based on the analysis of Ibbotson's retained damages expert (who has assumed, solely for purposes of his analysis, that Business Logic will prevail with regard to the issue of liability), and recognizing the uncertainty inherent in litigation and our intention to continue to vigorously defend the claims made by Business Logic, our best estimate of the range of possible loss is between $0 and $5.4 million, excluding punitive damages or attorneys' fees, both of which are recoverable in certain circumstances under the Illinois Trade Secrets Act. Business Logic's retained damages expert (who has also assumed for purposes of her estimate that Business Logic will prevail with regard to the issue of liability) estimated compensatory damages of $84 million, excluding punitive damages or attorneys' fees. Certain elements of the $84 million compensatory damages estimate were the subject of Ibbotson’s motion for partial summary judgment, which was granted on April 15, 2014. As a result, we believe the maximum compensatory damages award now recoverable is approximately $57 million, excluding prejudgment interest, punitive damages, and attorneys' fees. We dispute the conclusions reached and the methods employed by Business Logic's expert as to the remaining claims for damages. With regard to Business Logic's claim for injunctive relief, no reasonable estimate of loss or range of loss is possible. Morningstar and Ibbotson continue to vigorously contest all the claims against them in this matter. A jury trial is set to begin on July 7, 2014. We cannot predict the outcome of the proceeding. In addition to these proceedings, we are involved in legal proceedings and litigation that have arisen in the normal course of our business. Although the outcome of a particular proceeding can never be predicted, we do not believe that the result of any of these other matters will have a material adverse effect on our business, operating results, or financial position.

Contingencies

Life's Good S.T.A.B.L. Hedge Fund

In September 2011, three individual investors in Life's Good S.T.A.B.L. Mortgage hedge fund (LG), Marta Klass, Gregory Martin, and Richard Roellig, filed a complaint in the United States District Court for the Eastern District of Pennsylvania against LG, its principal Robert Stinson, and several other parties, including Morningstar, Inc. (the Klass Matter). The plaintiffs claim that Morningstar committed fraud and aided and abetted the other defendants' breach of fiduciary duty through the 5-star rating LG obtained from Morningstar. The plaintiffs seek unspecified damages. Hedge fund managers self-report their performance data to Morningstar. More than a year before the Klass Matter, in June 2010, the SEC filed suit against LG and other entities claiming they were part of a Ponzi scheme operated by Stinson. As a result, LG and the other entities were placed in court-appointed receivership. Morningstar was not part of the SEC suit or receivership. Since that time, the Receiver, as part of his duties, has been investigating whether to assert claims against third parties. Morningstar is aware of 14 lawsuits filed by the Receiver seeking to recover money for the fund.

In November 2011, Morningstar filed a motion to dismiss the Klass Matter. On behalf of the entities in receivership, the Receiver filed a motion to stay the proceedings because the Receivership Order does not permit suits against the entities in receivership without court permission. The court granted the Receiver's motion and stayed the Klass Matter. In April 2012, the Receiver filed a complaint against Morningstar, in which the Receiver claims that Morningstar is liable for contribution and aiding and abetting Stinson's breach of fiduciary duty and fraud through the 5-star rating LG obtained from Morningstar. The same day the Receiver filed his complaint, Morningstar sought leave from the court to file a countersuit against Stinson and two of his entities-Keystone State Capital Corporation and LG for, among other things, fraud, misrepresentation, and breach of user agreements. In June 2012, the court denied Morningstar's motion for leave to file suit. The court took no position on the merits of Morningstar's claims, and did not preclude us from renewing our motion to file a complaint at a later time, but deferred to the Receiver's request not to subject the receivership estate to additional litigation at this early point in the receivership. A bench trial related to the Receiver’s claims against Morningstar was held between January 13 and January 28, 2014. At trial, the Receiver claimed that Morningstar is liable under a contribution theory for all or part of a $14.5 million disgorgement judgment that the SEC obtained against the entities and individuals in receivership. Morningstar contested liability and damages at trial and believes it is not liable for any amount. The parties filed post-trial proposed findings of fact and conclusions of law on March 14, 2014. It is not known when the court will issue its decision.

We believe the allegations against Morningstar by the Klass plaintiffs and the Receiver have no legal or factual basis, and we plan to continue to vigorously contest the claims. We also intend to refile our affirmative claims against Stinson, Keystone, and LG at a later time consistent with the court's order. We cannot predict the outcome of the proceedings.

We have not provided an estimate of loss or range of loss in connection with this matter because no such estimate can reasonably be made.

Business Logic Holding Corporation

In November 2009, Business Logic Holding Corporation filed a complaint in the Circuit Court of Cook County, Illinois against Ibbotson Associates, Inc., one of our wholly owned subsidiaries, and Morningstar, Inc. relating to Ibbotson's prior commercial relationship with Business Logic. Business Logic is alleging breach of contract and trade secret misappropriation in connection with Ibbotson's development of a proprietary web-service software and user interface that connects plan participant data with the Ibbotson Wealth Forecasting Engine. Ibbotson and Morningstar answered the complaint, and Ibbotson asserted a counterclaim against Business Logic alleging trade secret misappropriation and breach of contract, also seeking damages and injunctive relief. Business Logic filed a motion for summary judgment on its breach of contract claim, which was denied on October 1, 2013. Business Logic also filed a summary motion seeking to dismiss Ibbotson’s counterclaim, which was granted on April 15, 2014. On the same date, the Court granted Ibbotson’s motion for partial summary judgment to dismiss claims on certain enumerated trade secrets, and granted its motion for partial summary judgment on certain damages issues.

Business Logic's complaint seeks, among other things, compensatory damages, punitive damages, attorneys' fees, and injunctive relief. With regard to compensatory damages, based on the analysis of Ibbotson's retained damages expert (who has assumed, solely for purposes of his analysis, that Business Logic will prevail with regard to the issue of liability), and recognizing the uncertainty inherent in litigation and our intention to continue to vigorously defend the claims made by Business Logic, our best estimate of the range of possible loss is between

$0 and $5.4 million, excluding punitive damages or attorneys' fees, both of which are recoverable in certain circumstances under the Illinois Trade Secrets Act.

Business Logic's retained damages expert (who has also assumed for purposes of her estimate that Business Logic will prevail with regard to the issue of liability) estimated compensatory damages of $84 million, excluding punitive damages or attorneys' fees. Certain elements of the $84 million compensatory damages estimate were the subject of Ibbotson’s motion for partial summary judgment, which was granted on April 15, 2014. As a result, we believe the maximum compensatory damages award now recoverable is approximately $57 million, excluding prejudgment interest, punitive damages, and attorneys' fees. We dispute the conclusions reached and the methods employed by Business Logic's expert as to the remaining claims for damages.

With regard to Business Logic's claim for injunctive relief, no reasonable estimate of loss or range of loss is possible.

Morningstar and Ibbotson continue to vigorously contest all the claims against them in this matter. A jury trial is set to begin on July 7, 2014. We cannot predict the outcome of the proceeding.

In addition to these proceedings, we are involved in legal proceedings and litigation that have arisen in the normal course of our business. Although the outcome of a particular proceeding can never be predicted, we do not believe that the result of any of these other matters will have a material adverse effect on our business, operating results, or financial position.