Contingent Liabilities	3 Months Ended
Mar. 31, 2015
Contingent Liabilities	18. Contingent Liabilities Commitments, Letters of Credit and Indemnifications. Northern Trust, in the normal course of business, enters into various types of commitments and issues letters of credit to meet the liquidity and credit enhancement needs of its clients. Legally binding commitments to extend credit generally have fixed expiration dates or other termination clauses. Since a significant portion of the commitments are expected to expire without being drawn upon, the total commitment amount does not necessarily represent future loans or liquidity requirements. Legally binding commitments to extend credit totaled $35.6 billion and $35.1 billion as of March 31, 2015, and December 31, 2014, respectively, excluding $477.2 million and $481.4 million of commitments participated to others as of March 31, 2015, and December 31, 2014, respectively. Standby letters of credit obligate Northern Trust to meet certain financial obligations of its clients, if, under the contractual terms of the agreement, the clients are unable to do so. These instruments are primarily issued to support public and private financial commitments, including commercial paper, bond financing, initial margin requirements on futures exchanges and similar transactions. Northern Trust is obligated to meet the entire financial obligation of these agreements and in certain cases is able to recover the amounts paid through recourse against collateral received or other participants. Standby letters of credit outstanding were $4.4 billion and $4.5 billion as of March 31, 2015, and December 31, 2014, respectively. As part of its securities custody activities and at the direction of its clients, Northern Trust lends securities owned by clients to borrowers who are reviewed and approved by the Northern Trust Counterparty Risk Management Committee. In connection with these activities, Northern Trust has issued indemnifications to certain clients against certain losses that are a direct result of a borrower’s failure to return securities when due, should the value of such securities exceed the value of the collateral required to be posted. Borrowers are required to collateralize fully securities received with cash or marketable securities. As securities are loaned, collateral is maintained at a minimum of 100% of the fair value of the securities plus accrued interest. The collateral is revalued on a daily basis. The amount of securities loaned as of March 31, 2015, and December 31, 2014, subject to indemnification was $105.5 billion and $98.1 billion, respectively. Because of the credit quality of the borrowers and the requirement to collateralize fully securities borrowed, management believes that the exposure to credit loss from this activity is not significant and no liability was recorded as of March 31, 2015, or December 31, 2014, related to these indemnifications. Legal Proceedings. In the normal course of business, the Corporation and its subsidiaries are routinely defendants in or parties to a number of pending and threatened legal actions, including, but not limited to, actions brought on behalf of various claimants or classes of claimants, regulatory matters, employment matters and challenges from tax authorities regarding the amount of taxes due. In certain of these actions and proceedings, claims for substantial monetary damages or adjustments to recorded tax liabilities are asserted. Based on current knowledge, after consultation with legal counsel and after taking into account current accruals, management does not believe that losses, if any, arising from pending litigation or threatened legal actions or regulatory matters will have a material adverse effect on the consolidated financial position or liquidity of the Corporation, although such matters could have a material adverse effect on the Corporation’s operating results for a particular period. Under GAAP, (i) an event is “probable” if the “future event or events are likely to occur”; (ii) an event is “reasonably possible” if “the chance of the future event or events occurring is more than remote but less than likely”; and (iii) an event is “remote” if “the chance of the future event or events occurring is slight.” For the reasons set out in this paragraph, the outcome of some matters is inherently difficult to predict and/or the range of loss cannot be reasonably estimated. This may be the case in matters that (i) will be decided by a jury, (ii) are in early stages, (iii) involve uncertainty as to the likelihood of a class being certified or the ultimate size of the class, (iv) are subject to appeals or motions, (v) involve significant factual issues to be resolved, including with respect to the amount of damages, (vi) do not specify the amount of damages sought or (vii) seek very large damages based on novel and complex damage and liability legal theories. Accordingly, the Corporation cannot reasonably estimate the eventual outcome of these pending matters, the timing of their ultimate resolution or what the eventual loss, fines or penalties, if any, related to each pending matter will be. In accordance with applicable accounting guidance, the Corporation records accruals for litigation and regulatory matters when those matters present loss contingencies that are both probable and reasonably estimable. When loss contingencies are not both probable and reasonably estimable, the Corporation does not record accruals. No material accruals have been recorded for pending litigation or threatened legal actions or regulatory matters. For a limited number of the matters for which a loss is reasonably possible in future periods, whether in excess of an accrued liability or where there is no accrued liability, the Corporation is able to estimate a range of possible loss. As of March 31, 2015, the Corporation has estimated the upper end of the range of reasonably possible losses for these matters to be approximately $125 million in the aggregate. This aggregate amount of reasonably possible loss is based upon currently available information and is subject to significant judgment and a variety of assumptions and known and unknown uncertainties. The matters underlying the estimated range will change from time to time, and actual results will vary significantly from the current estimate. In certain other pending matters, there may be a range of reasonably possible losses (including reasonably possible losses in excess of amounts accrued) that cannot be reasonably estimated for the reasons described above. Such matters are not included in the estimate of reasonably possible losses identified above. A number of participants in Northern Trust’s securities lending program, which is associated with its asset servicing business, have commenced either individual lawsuits or purported class actions in which they claim, among other things, that Northern Trust failed to exercise prudence in the investment management of the collateral received from the borrowers of the securities, resulting in losses that they seek to recover. The cases assert various contractual, statutory and common law claims, including claims for breach of fiduciary duty under common law and under the Employee Retirement Income Security Act (ERISA). In 2013, Northern Trust recorded a $19.2 million pre-tax charge in connection with an agreement to resolve certain claims related to two of these lawsuits, the settlement of which remains pending while awaiting court approval. Other lawsuits and claims related to securities lending are not part of the proposed settlement, and remain pending. As previously disclosed in April 2014, Northern Trust remains subject to an investigation by the U.S. Securities and Exchange Commission (SEC) related to Northern Trust’s securities lending activities. Northern Trust continues to cooperate with the SEC in this investigation. In January 2015, the Public Prosecutor’s Office of France recommended that certain charges be brought against Northern Trust Fiduciary Services (Guernsey) Limited (“NTFS”), an indirect subsidiary of the Corporation, relating to the administration of two trusts for which NTFS serves as trustee. In April 2015, a French investigating magistrate judge charged NTFS with complicity in estate tax fraud. NTFS will contest the criminal charge in the French court. As trustee, NTFS provided no tax advice and had no involvement in the preparation or filing of the challenged estate tax filings. Visa Membership. Northern Trust, as a member of Visa U.S.A. Inc. and in connection with the initial public offering of Visa Inc. (Visa), received shares of restricted stock in Visa. As of March 31, 2015, the Visa shares held by Northern Trust are recorded at their original cost basis of zero and have restrictions as to their sale or transfer. Northern Trust is obligated to indemnify Visa for losses resulting from certain indemnified litigation relating to interchange fees and has been required to recognize, at its estimated fair value in accordance with GAAP, a guarantee liability arising from such litigation that has not yet settled. During 2007, Northern Trust recorded liabilities relating to Visa indemnified litigation. Subsequently, Visa established an escrow account to cover the settlements of, or judgments in, indemnified litigation. The fundings by Visa of its escrow account have resulted in reductions of Northern Trust’s indemnification liability. Northern Trust’s indemnification liability was fully eliminated as of December 31, 2011. On October 19, 2012, Visa signed a settlement agreement with plaintiff representatives for binding settlement of the indemnified litigation. On January 14, 2014, the trial court entered a final judgment order approving the settlement with the class plaintiffs, which is subject to appeal. A number of objectors have appealed from that order and more than 30 opt-out cases have been filed by merchants in various federal district courts. While the ultimate resolution of the indemnified litigation and the timing for removal of selling restrictions on the Visa shares are highly uncertain, Northern Trust anticipates that the value of its Visa shares will be adequate to offset any remaining indemnification obligations related to Visa litigation.

18. Contingent Liabilities

Commitments, Letters of Credit and Indemnifications. Northern Trust, in the normal course of business, enters into various types of commitments and issues letters of credit to meet the liquidity and credit enhancement needs of its clients.

Legally binding commitments to extend credit generally have fixed expiration dates or other termination clauses. Since a significant portion of the commitments are expected to expire without being drawn upon, the total commitment amount does not necessarily represent future loans or liquidity requirements. Legally binding commitments to extend credit totaled $35.6 billion and $35.1 billion as of March 31, 2015, and December 31, 2014, respectively, excluding $477.2 million and $481.4 million of commitments participated to others as of March 31, 2015, and December 31, 2014, respectively.

Standby letters of credit obligate Northern Trust to meet certain financial obligations of its clients, if, under the contractual terms of the agreement, the clients are unable to do so. These instruments are primarily issued to support public and private financial commitments, including commercial paper, bond financing, initial margin requirements on futures exchanges and similar transactions. Northern Trust is obligated to meet the entire financial obligation of these agreements and in certain cases is able to recover the amounts paid through recourse against collateral received or other participants. Standby letters of credit outstanding were $4.4 billion and $4.5 billion as of March 31, 2015, and December 31, 2014, respectively.

As part of its securities custody activities and at the direction of its clients, Northern Trust lends securities owned by clients to borrowers who are reviewed and approved by the Northern Trust Counterparty Risk Management Committee. In connection with these activities, Northern Trust has issued indemnifications to certain clients against certain losses that are a direct result of a borrower’s failure to return securities when due, should the value of such securities exceed the value of the collateral required to be posted. Borrowers are required to collateralize fully securities received with cash or marketable securities. As securities are loaned, collateral is maintained at a minimum of 100% of the fair value of the securities plus accrued interest. The collateral is revalued on a daily basis. The amount of securities loaned as of March 31, 2015, and December 31, 2014, subject to indemnification was $105.5 billion and $98.1 billion, respectively. Because of the credit quality of the borrowers and the requirement to collateralize fully securities borrowed, management believes that the exposure to credit loss from this activity is not significant and no liability was recorded as of March 31, 2015, or December 31, 2014, related to these indemnifications.

Legal Proceedings. In the normal course of business, the Corporation and its subsidiaries are routinely defendants in or parties to a number of pending and threatened legal actions, including, but not limited to, actions brought on behalf of various claimants or classes of claimants, regulatory matters, employment matters and challenges from tax authorities regarding the amount of taxes due. In certain of these actions and proceedings, claims for substantial monetary damages or adjustments to recorded tax liabilities are asserted.

Based on current knowledge, after consultation with legal counsel and after taking into account current accruals, management does not believe that losses, if any, arising from pending litigation or threatened legal actions or regulatory matters will have a material adverse effect on the consolidated financial position or liquidity of the Corporation, although such matters could have a material adverse effect on the Corporation’s operating results for a particular period.

Under GAAP, (i) an event is “probable” if the “future event or events are likely to occur”; (ii) an event is “reasonably possible” if “the chance of the future event or events occurring is more than remote but less than likely”; and (iii) an event is “remote” if “the chance of the future event or events occurring is slight.”

For the reasons set out in this paragraph, the outcome of some matters is inherently difficult to predict and/or the range of loss cannot be reasonably estimated. This may be the case in matters that (i) will be decided by a jury, (ii) are in early stages, (iii) involve uncertainty as to the likelihood of a class being certified or the ultimate size of the class, (iv) are subject to appeals or motions, (v) involve significant factual issues to be resolved, including with respect to the amount of damages, (vi) do not specify the amount of damages sought or (vii) seek very large damages based on novel and complex damage and liability legal theories. Accordingly, the Corporation cannot reasonably estimate the eventual outcome of these pending matters, the timing of their ultimate resolution or what the eventual loss, fines or penalties, if any, related to each pending matter will be.

In accordance with applicable accounting guidance, the Corporation records accruals for litigation and regulatory matters when those matters present loss contingencies that are both probable and reasonably estimable. When loss contingencies are not both probable and reasonably estimable, the Corporation does not record accruals. No material accruals have been recorded for pending litigation or threatened legal actions or regulatory matters.

For a limited number of the matters for which a loss is reasonably possible in future periods, whether in excess of an accrued liability or where there is no accrued liability, the Corporation is able to estimate a range of possible loss. As of March 31, 2015, the Corporation has estimated the upper end of the range of reasonably possible losses for these matters to be approximately $125 million in the aggregate. This aggregate amount of reasonably possible loss is based upon currently available information and is subject to significant judgment and a variety of assumptions and known and unknown uncertainties. The matters underlying the estimated range will change from time to time, and actual results will vary significantly from the current estimate.

In certain other pending matters, there may be a range of reasonably possible losses (including reasonably possible losses in excess of amounts accrued) that cannot be reasonably estimated for the reasons described above. Such matters are not included in the estimate of reasonably possible losses identified above.

A number of participants in Northern Trust’s securities lending program, which is associated with its asset servicing business, have commenced either individual lawsuits or purported class actions in which they claim, among other things, that Northern Trust failed to exercise prudence in the investment management of the collateral received from the borrowers of the securities, resulting in losses that they seek to recover. The cases assert various contractual, statutory and common law claims, including claims for breach of fiduciary duty under common law and under the Employee Retirement Income Security Act (ERISA). In 2013, Northern Trust recorded a $19.2 million pre-tax charge in connection with an agreement to resolve certain claims related to two of these lawsuits, the settlement of which remains pending while awaiting court approval. Other lawsuits and claims related to securities lending are not part of the proposed settlement, and remain pending.

As previously disclosed in April 2014, Northern Trust remains subject to an investigation by the U.S. Securities and Exchange Commission (SEC) related to Northern Trust’s securities lending activities. Northern Trust continues to cooperate with the SEC in this investigation.

In January 2015, the Public Prosecutor’s Office of France recommended that certain charges be brought against Northern Trust Fiduciary Services (Guernsey) Limited (“NTFS”), an indirect subsidiary of the Corporation, relating to the administration of two trusts for which NTFS serves as trustee. In April 2015, a French investigating magistrate judge charged NTFS with complicity in estate tax fraud. NTFS will contest the criminal charge in the French court. As trustee, NTFS provided no tax advice and had no involvement in the preparation or filing of the challenged estate tax filings.

Visa Membership. Northern Trust, as a member of Visa U.S.A. Inc. and in connection with the initial public offering of Visa Inc. (Visa), received shares of restricted stock in Visa. As of March 31, 2015, the Visa shares held by Northern Trust are recorded at their original cost basis of zero and have restrictions as to their sale or transfer.

Northern Trust is obligated to indemnify Visa for losses resulting from certain indemnified litigation relating to interchange fees and has been required to recognize, at its estimated fair value in accordance with GAAP, a guarantee liability arising from such litigation that has not yet settled. During 2007, Northern Trust recorded liabilities relating to Visa indemnified litigation. Subsequently, Visa established an escrow account to cover the settlements of, or judgments in, indemnified litigation. The fundings by Visa of its escrow account have resulted in reductions of Northern Trust’s indemnification liability. Northern Trust’s indemnification liability was fully eliminated as of December 31, 2011. On October 19, 2012, Visa signed a settlement agreement with plaintiff representatives for binding settlement of the indemnified litigation. On January 14, 2014, the trial court entered a final judgment order approving the settlement with the class plaintiffs, which is subject to appeal. A number of objectors have appealed from that order and more than 30 opt-out cases have been filed by merchants in various federal district courts.

While the ultimate resolution of the indemnified litigation and the timing for removal of selling restrictions on the Visa shares are highly uncertain, Northern Trust anticipates that the value of its Visa shares will be adequate to offset any remaining indemnification obligations related to Visa litigation.