Consolidated Statements Of Comprehensive Income (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Interest income:
Interest income	$ 383	$ 399
Interest expense	86us-gaap_InterestExpense	108us-gaap_InterestExpense
Net interest income	297us-gaap_InterestIncomeExpenseNet	291us-gaap_InterestIncomeExpenseNet
Other income, net:
Gain (loss) on sale of agency securities, net	36	(19)
Loss on derivative instruments and other securities, net	(549)	(378)
Total other income, net	(513)us-gaap_NoninterestIncome	(397)us-gaap_NoninterestIncome
Expenses:
Management fees	30us-gaap_ManagementFeeExpense	29us-gaap_ManagementFeeExpense
General and administrative expenses	6us-gaap_GeneralAndAdministrativeExpense	6us-gaap_GeneralAndAdministrativeExpense
Total expenses	36us-gaap_OperatingExpenses	35us-gaap_OperatingExpenses
Net loss	(252)us-gaap_NetIncomeLoss	(141)us-gaap_NetIncomeLoss
Dividend on preferred stock	7	3
Net loss attributable to common stockholders	(259)	(144)
Other comprehensive income (loss):
Unrealized Gains and (Losses), Net	391	521
Unrealized gain on derivative instruments, net	29	43
Other comprehensive income (loss)	420	564
Comprehensive income	168us-gaap_ComprehensiveIncomeNetOfTax	423us-gaap_ComprehensiveIncomeNetOfTax
Comprehensive income available to common stockholders	$ 161	$ 420
Weighted average number of common shares outstanding-basic and diluted (shares)	352.8	354.8
Net loss per common share - basic and diluted (dollars per share)	$ (0.73)us-gaap_EarningsPerShareBasicAndDiluted	$ (0.41)us-gaap_EarningsPerShareBasicAndDiluted
Comprehensive income per common share - basic and diluted	$ 0.46	$ 1.18
Dividends declared per common share	$ 0.66	$ 0.65

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Amount of operating interest income, including amortization and accretion of premiums and discounts, on securitized, pass-through debt securities collateralized by real estate mortgage loans.

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The total amount of noninterest income which may be derived from: (1) fees and commissions; (2) premiums earned; (3) insurance policy charges; (4) the sale or disposal of assets; and (5) other sources not otherwise specified.

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Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense.

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Amount after tax, before reclassification adjustments, of unrealized holding gain (loss) on available-for-sale securities.

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The amount of preferred stock dividends that is an adjustment to net income apportioned to common stockholders.

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Average number of shares or units issued and outstanding that are used in calculating basic and diluted earnings per share (EPS).

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