Analysis of Contractual Maturities and Next Call Dates of Outstanding Repurchase Agreements (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Amount
Repurchase agreements	$ 3,425,000	$ 4,125,000
Weighted Average Interest Rate
Contractual Maturity Over 90 days, Weighted Average Interest Rate	3.44%
Contractual Maturity
Amount
2015	100,000
2016	182,000
2017	450,000
2018	1,600,000
2020	513,000
2023	580,000
Repurchase agreements	3,425,000
Weighted Average Interest Rate
2015	2.17%
2016	3.25%
2017	4.04%
2018	3.48%
2020	3.32%
2023	3.24%
Contractual Maturity Over 90 days, Weighted Average Interest Rate	3.44%
Earlier of Contractual Maturity or Next Call Date
Amount
2014	2,100,000
2015	100,000
2016	595,000
2017	380,000
2018	250,000
Repurchase agreements	$ 3,425,000
Weighted Average Interest Rate
2014	3.55%
2015	2.17%
2016	3.54%
2017	3.14%
2018	3.23%
Contractual Maturity Over 90 days, Weighted Average Interest Rate	3.44%

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Securities Sold Under Agreements To Repurchase Maturities Summary Due Within Five Years Of Balance Sheet Date

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Securities Sold Under Agreements To Repurchase Maturities Summary Due Within Four Years Of Balance Sheet Date

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Amount of cash received as security in return for loaning securities to another party which are due within one year of the Balance Sheet date.

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Securities Sold Under Agreements to Repurchase Maturities Summary Due Within Seven Years of Balance Sheet Date

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Securities Sold Under Agreements to Repurchase Maturities Summary Due Within Ten Years of Balance Sheet Date

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Securities Sold Under Agreements To Repurchase Maturities Summary Due Within Three Years Of Balance Sheet Date

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The weighted average interest rate applicable to the cash received as security in return for loaning securities to another party which are due from five to six years of the Balance Sheet date.

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The weighted average interest rate applicable to the cash received as security in return for loaning securities to another party which are due from four to five years of the Balance Sheet date.

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The weighted average interest rate applicable to the cash received as security in return for loaning securities to another party which are due within one year of the Balance Sheet date.

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The weighted average interest rate applicable to the cash received as security in return for loaning securities to another party which are due from one to two years of the Balance Sheet date.

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Securities Sold under Agreements to Repurchase, Maturities Summary, Weighted Average Interest Rate, Three to Four Years from Balance Sheet Date

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Interest rate on the amount to be repaid to the counterparty to the repurchase agreement when the carrying amount (or market value, if higher than the carrying amount) of securities or other assets sold under the repurchase agreement exceeds 10 percent of total assets.

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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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