Basis of Presentation	9 Months Ended
Sep. 30, 2011
Basis of Presentation [Abstract]
Basis of Presentation	2. Basis of Presentation The accompanying consolidated financial statements include the accounts of Hudson City Bancorp and its wholly-owned subsidiary, Hudson City Savings. In our opinion, all the adjustments (consisting of normal and recurring adjustments) necessary for a fair presentation of the consolidated financial condition and consolidated results of operations for the unaudited periods presented have been included. The results of operations and other data presented for the three and nine month periods ended September 30, 2011 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2011. In preparing the consolidated financial statements, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the statements of financial condition and the results of operations for the period. Actual results could differ from these estimates. The allowance for loan losses (“ALL”) is a material estimate that is particularly susceptible to near-term change. The current economic environment has increased the degree of uncertainty inherent in this material estimate. In addition, bank regulators, as an integral part of their supervisory function, periodically review our ALL. These regulatory agencies have the ability to require us, as they can require all banks, to increase our provision for loan losses or to recognize further charge-offs based upon their judgments, which may be different from ours. Any increase in the ALL required by these regulatory agencies could adversely affect our financial condition and results of operations. FASB guidance requires that goodwill and intangible assets with indefinite lives be tested for impairment at least annually using a fair-value based two-step approach. The first step (“Step 1”) used to identify potential impairment involves comparing each reporting unit’s estimated fair value to its carrying amount, including goodwill. If the estimated fair value of a reporting unit exceeds its carrying amount, goodwill is not considered to be impaired. If the carrying amount exceeds the estimated fair value, there is an indication of potential impairment and the second step (“Step 2”) is performed to measure the amount. Step 2 involves calculating an implied fair value of goodwill for each reporting unit for which impairment was indicated in Step 1. The implied fair value of goodwill is determined in a manner similar to the amount of goodwill calculated in a business combination by measuring the excess of the estimated fair value of the reporting unit, as determined in Step 1, over the aggregate estimated fair values of the individual assets, liabilities, and identifiable intangibles, as if the reporting unit was being acquired at the impairment test date. Due to declines in our common stock price during the third quarter of 2011, we re-assessed goodwill for impairment. Based on Step 1 of our analysis, the estimated fair value of the Company was less than the Company’s book value which indicated potential goodwill impairment. For Step 2 of the goodwill impairment test, we compared the fair value of the Company as determined in Step 1 with the fair value of the assets and liabilities of the Company to calculate an implied goodwill. Based on our Step 2 analysis, the implied goodwill of the Company exceeded the carrying value of goodwill. Therefore, we did not recognize any impairment of goodwill or other intangible assets during the nine months ended September 30, 2011. The estimation of the fair value of the Company and the fair value of the Company’s assets and liabilities requires the use of estimates and assumptions that are subject to a greater degree of uncertainty. The fair values of our assets and liabilities are sensitive to, among other things, changes in market interest rates. The unrealized loss on the Company’s assets and liabilities had the effect of increasing the estimated implied value of goodwill. The results of the Step 2 analysis were attributable to several factors. The primary drivers were the unrealized loss on the Company’s borrowings. In addition, the estimated fair value of the Company is based on the market price of our common stock and the change-in-control premiums for recent acquisitions. The results of the Step 2 analysis are highly sensitive to these measurements, as well as the key assumptions in determining the estimated fair value of the Company. As a result of the current volatility in market and economic conditions, these estimates and assumptions are subject to change in the near-term and may result in the impairment in future periods of some or all of the goodwill on our balance sheet. Goodwill amounted to $152.1 million at September 30, 2011. Certain information and note disclosures usually included in financial statements prepared in accordance with U.S. generally accepted accounting principles have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) for the preparation of the Form 10-Q. The consolidated financial statements presented should be read in conjunction with Hudson City Bancorp’s audited consolidated financial statements and notes to consolidated financial statements included in Hudson City Bancorp’s 2010 Annual Report to Shareholders and incorporated by reference into Hudson City Bancorp’s 2010 Annual Report on Form 10-K.

2. Basis of Presentation

The accompanying consolidated financial statements include the accounts of Hudson City Bancorp and its wholly-owned subsidiary, Hudson City Savings.

In our opinion, all the adjustments (consisting of normal and recurring adjustments) necessary for a fair presentation of the consolidated financial condition and consolidated results of operations for the unaudited periods presented have been included. The results of operations and other data presented for the three and nine month periods ended September 30, 2011 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2011. In preparing the consolidated financial statements, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the statements of financial condition and the results of operations for the period. Actual results could differ from these estimates. The allowance for loan losses (“ALL”) is a material estimate that is particularly susceptible to near-term change. The current economic environment has increased the degree of uncertainty inherent in this material estimate. In addition, bank regulators, as an integral part of their supervisory function, periodically review our ALL. These regulatory agencies have the ability to require us, as they can require all banks, to increase our provision for loan losses or to recognize further charge-offs based upon their judgments, which may be different from ours. Any increase in the ALL required by these regulatory agencies could adversely affect our financial condition and results of operations.

FASB guidance requires that goodwill and intangible assets with indefinite lives be tested for impairment at least annually using a fair-value based two-step approach. The first step (“Step 1”) used to identify potential impairment involves comparing each reporting unit’s estimated fair value to its carrying amount, including goodwill. If the estimated fair value of a reporting unit exceeds its carrying amount, goodwill is not considered to be impaired. If the carrying amount exceeds the estimated fair value, there is an indication of potential impairment and the second step (“Step 2”) is performed to measure the amount. Step 2 involves calculating an implied fair value of goodwill for each reporting unit for which impairment was indicated in Step 1. The implied fair value of goodwill is determined in a manner similar to the amount of goodwill calculated in a business combination by measuring the excess of the estimated fair value of the reporting unit, as determined in Step 1, over the aggregate estimated fair values of the individual assets, liabilities, and identifiable intangibles, as if the reporting unit was being acquired at the impairment test date.

Due to declines in our common stock price during the third quarter of 2011, we re-assessed goodwill for impairment. Based on Step 1 of our analysis, the estimated fair value of the Company was less than the Company’s book value which indicated potential goodwill impairment. For Step 2 of the goodwill impairment test, we compared the fair value of the Company as determined in Step 1 with the fair value of the assets and liabilities of the Company to calculate an implied goodwill. Based on our Step 2 analysis, the implied goodwill of the Company exceeded the carrying value of goodwill. Therefore, we did not recognize any impairment of goodwill or other intangible assets during the nine months ended September 30, 2011. The estimation of the fair value of the Company and the fair value of the Company’s assets and liabilities requires the use of estimates and assumptions that are subject to a greater degree of uncertainty. The fair values of our assets and liabilities are sensitive to, among other things, changes in market interest rates. The unrealized loss on the Company’s assets and liabilities had the effect of increasing the estimated implied value of goodwill. The results of the Step 2 analysis were attributable to several factors. The primary drivers were the unrealized loss on the Company’s borrowings. In addition, the estimated fair value of the Company is based on the market price of our common stock and the change-in-control premiums for recent acquisitions. The results of the Step 2 analysis are highly sensitive to these measurements, as well as the key assumptions in determining the estimated fair value of the Company. As a result of the current volatility in market and economic conditions, these estimates and assumptions are subject to change in the near-term and may result in the impairment in future periods of some or all of the goodwill on our balance sheet. Goodwill amounted to $152.1 million at September 30, 2011.

Certain information and note disclosures usually included in financial statements prepared in accordance with U.S. generally accepted accounting principles have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) for the preparation of the Form 10-Q. The consolidated financial statements presented should be read in conjunction with Hudson City Bancorp’s audited consolidated financial statements and notes to consolidated financial statements included in Hudson City Bancorp’s 2010 Annual Report to Shareholders and incorporated by reference into Hudson City Bancorp’s 2010 Annual Report on Form 10-K.