Consolidated Statements of Condition (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Consolidated Statements of Condition
Held-to-maturity, Market value (in dollars)	$ 2,400	$ 2,400
Available-for-sale, Amortized cost (in dollars)	5,102,700	5,423,189
Common shares, par value (in dollars per share)	$ 1.00	$ 1.00
Common shares, Authorized shares	275,000,000	275,000,000
Common shares, issued shares	95,725,560	95,724,517
Accumulated other comprehensive income, comprehensive loss related to other-than-temporary impairment for non-credit related issues (in dollars)	$ (7,234)	$ (6,811)
Treasury, shares	28,537,180	28,537,180

Total of accumulated other comprehensive loss related to that portion of other than temporary impairment (OTTI) due to factors other than credit losses on debt securities categorized either as available-for-sale or held-to-maturity that an entity does not intend to sell and which it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis of the debt security. The amount represented by this item is net of tax, as applicable.

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