Other Expenses	12 Months Ended
Dec. 31, 2011
Other Expenses [Abstract]
Other Expenses	Note 21. Other Expenses In 2010, we recorded an aggregate pre-tax charge of $414 million, including associated legal costs of $9 million, in our consolidated statement of income with respect to the cash collateral pools underlying SSgA-managed investment funds engaged in securities lending, as well as the cash collateral pools underlying our agency lending program. In connection with the charge, we made a one-time cash contribution of $330 million to the cash collateral pools and liquidating trusts underlying the SSgA lending funds. In light of our assessment with respect to previously disclosed asserted and unasserted claims and our evaluation of the ultimate resolution of such claims, as well as the effect of the redemption restrictions originally imposed by SSgA on the lending funds and other considerations, we elected to make the cash contribution, which restored the net asset value per unit of the underlying cash collateral pools to $1.00 as of June 30, 2010. As a result of this action, SSgA removed the redemption restrictions from the SSgA lending funds in August 2010. The pre-tax charge also included the establishment of a $75 million reserve to address potential inconsistencies in connection with our implementation of the redemption restrictions applicable to the collateral pools underlying our agency lending program. This charge was based on the results of a review of our implementation of the redemption restrictions with respect to participants in the agency lending collateral pools, and our assessment of the amount required to compensate clients for the dilutive effect of redemptions which may not have been consistent with the intent of the policy. In May 2011, we distributed substantially all of the reserve to "net providers" of liquidity in such pools, equal to the estimated excess liquidity used by "net consumers" of liquidity in those pools. In 2009, the Staff of the SEC provided State Street Bank with a "Wells" notice related to the SEC's ongoing investigation into disclosures and management by SSgA of certain of its active fixed-income strategies during 2007 and prior periods. Subsequent to the receipt of the Wells notice, we engaged in discussions with the SEC and other governmental and regulatory authorities regarding a potential settlement of this matter. Based on such discussions in 2009, we determined it appropriate to increase our reserve, initially established in 2007 to address litigation exposure and other costs associated with SSgA's management of these fixed-income strategies, by $250 million, to take into account such a potential settlement with these governmental authorities and the other ongoing litigation related to the active fixed-income strategies. As a result, we recorded a provision of $250 million in our 2009 consolidated statement of income related to our estimate of this legal exposure. We settled regulatory inquiries related to this exposure in 2010.

Note 21. Other Expenses

In 2010, we recorded an aggregate pre-tax charge of $414 million, including associated legal costs of $9 million, in our consolidated statement of income with respect to the cash collateral pools underlying SSgA-managed investment funds engaged in securities lending, as well as the cash collateral pools underlying our agency lending program. In connection with the charge, we made a one-time cash contribution of $330 million to the cash collateral pools and liquidating trusts underlying the SSgA lending funds. In light of our assessment with respect to previously disclosed asserted and unasserted claims and our evaluation of the ultimate resolution of such claims, as well as the effect of the redemption restrictions originally imposed by SSgA on the lending funds and other considerations, we elected to make the cash contribution, which restored the net asset value per unit of the underlying cash collateral pools to $1.00 as of June 30, 2010. As a result of this action, SSgA removed the redemption restrictions from the SSgA lending funds in August 2010.

The pre-tax charge also included the establishment of a $75 million reserve to address potential inconsistencies in connection with our implementation of the redemption restrictions applicable to the collateral pools underlying our agency lending program. This charge was based on the results of a review of our implementation of the redemption restrictions with respect to participants in the agency lending collateral pools, and our assessment of the amount required to compensate clients for the dilutive effect of redemptions which may not have been consistent with the intent of the policy. In May 2011, we distributed substantially all of the reserve to "net providers" of liquidity in such pools, equal to the estimated excess liquidity used by "net consumers" of liquidity in those pools.

In 2009, the Staff of the SEC provided State Street Bank with a "Wells" notice related to the SEC's ongoing investigation into disclosures and management by SSgA of certain of its active fixed-income strategies during 2007 and prior periods. Subsequent to the receipt of the Wells notice, we engaged in discussions with the SEC and other governmental and regulatory authorities regarding a potential settlement of this matter. Based on such discussions in 2009, we determined it appropriate to increase our reserve, initially established in 2007 to address litigation exposure and other costs associated with SSgA's management of these fixed-income strategies, by $250 million, to take into account such a potential settlement with these governmental authorities and the other ongoing litigation related to the active fixed-income strategies. As a result, we recorded a provision of $250 million in our 2009 consolidated statement of income related to our estimate of this legal exposure. We settled regulatory inquiries related to this exposure in 2010.