Investments in Securities Other-than-temporary Impairments 3 (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended									12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011		Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Out-of-period adjustment due to an overstatement of income and amortized cost.	$ 748	$ 789	$ 1,035	$ 727	$ (248)	[1]	$ 1,160	$ 1,152	$ 1,213	$ 3,299		$ 3,277		$ 5,290
Available-for-sale Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance, beginning of period				8,915					8,215	8,915		8,215
Additions for the credit component on debt securities for which OTTI was not previously recognized										15		23
Additions for the credit component on debt securities for which OTTI was previously recognized										698		285
Reductions for securities no longer in portfolio at period end										(5)		(7)
(Reductions) additions for amortization resulting from changes in cash flows expected to be collected over the remaining life of the securities										(409)	[2]	399	[2]
Balance, end of period	9,214				8,915					9,214		8,915
Out-of-Period Adjustment [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Out-of-period adjustment due to an overstatement of income and amortized cost.					$ (1,200)							$ 727

[1] Includes an out-of-period adjustment of $933 million comprised of $1.2 billion to reduce “Interest Income: Available-for-sale securities” offset by a $264 million reduction to “Other-than-temporary impairments” in our consolidated statement of operations and comprehensive loss for the three months ended December 31, 2011.

[2] Amount includes out-of-period adjustment of $727 million in 2011 due to an overstatement of income and amortized cost.