Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

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Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, That Will Be Amortized into Interest Expense

+ References

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- Definition

Number Of Derivative Counterparty

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- Definition

Accumulated change, net of tax, in accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges. Includes an entity's share of an equity investee's Increase or Decrease in deferred hedging gains or losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 11

-URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e637-108580

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-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 14A

-URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669686-108580

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-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 10A

-Subparagraph (d)

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-Name Accounting Standards Codification

-Topic 815

-SubTopic 30

-Section 50

-Paragraph 2

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- Definition

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4A

-Subparagraph (b)

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-Subparagraph (a),(c),(d),(e)

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- Definition

The effective portion of loss reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

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-Paragraph 4C

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Derivative Financial Instruments - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Derivative [Line Items]
Notional Amount	$ 3,663,084,000invest_DerivativeNotionalAmount	$ 1,488,922,000invest_DerivativeNotionalAmount
Net unrealized losses on interest rate agreements accounted for as cash flow hedges	(30,000,000)	(16,000,000)
Hedges decreased in value recorded as a component of interest expense			15,000,000
Acacia
Derivative [Line Items]
Hedges decreased in value recorded as a component of interest expense			11,000,000
Redwood
Derivative [Line Items]
Number of outstanding derivative agreements with counterparties	6
Cash Flow Hedging \| Interest Rate Swaps
Derivative [Line Items]
Notional Amount	140,000,000
Valuation adjustments on derivatives	(30,000,000)	32,000,000	4,000,000
Unsecuritized Residential and Commercial Loans \| Other Investments
Derivative [Line Items]
Valuation adjustments on derivatives	(7,800,000)	200,000	(12,600,000)
Unsecuritized Residential and Commercial Loans \| Unsecuritized Loans
Derivative [Line Items]
Valuation adjustments on derivatives	(31,000,000)	51,000,000	(11,000,000)
Unsecuritized Residential and Commercial Loans \| Interest Rate Contract
Derivative [Line Items]
Notional Amount	920,000,000
Unsecuritized Residential and Commercial Loans \| Futures
Derivative [Line Items]
Notional Amount	90,000,000
Unsecuritized Residential and Commercial Loans \| TBAs
Derivative [Line Items]
Notional Amount	2,200,000,000
Loan Purchase and Forward Sales Commitments
Derivative [Line Items]
Valuation adjustments on derivatives	14,000,000	(1,000,000)
Maximum
Derivative [Line Items]
Hedges decreased in value recorded as a component of interest expense	1,000,000	1,000,000
Maximum \| Interest Rate Swaps
Derivative [Line Items]
Accumulated other comprehensive loss that will be amortized into interest expense	$ (1,000,000)