Short-term Funding Composition (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Short-term Debt [Abstract]
Federal funds purchased	$ 109,770us-gaap_FederalFundsPurchased	$ 56,195us-gaap_FederalFundsPurchased
Securities sold under agreements to repurchase	384,221	419,247
Federal Home Loan Bank ("FHLB") advances	500,000	200,000
Commercial paper	74,297us-gaap_CommercialPaper	65,484us-gaap_CommercialPaper
Short-term funding	$ 1,068,288us-gaap_ShortTermBorrowings	$ 740,926us-gaap_ShortTermBorrowings

Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days.

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Amount, after the effects of master netting arrangements, of funds outstanding borrowed in the form of a security resale agreement between the entity and another party for the purchase and resale of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement.

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- Definition

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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