Investments in Securities Other-than-temporary Impairments 3 (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Noncredit portion of other-than-temporary impairments recognized in other comprehensive income (loss)	$ (7)	$ 21	$ (125)	$ 408
Available-for-sale securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance, beginning of period	8,964	9,366	9,214	8,915
Additions for the credit component on debt securities for which OTTI was not previously recognized	0	11	7	13
Additions for the credit component on debt securities for which OTTI was previously recognized	1	27	9	688
Reductions for securities no longer in portfolio at period end	(457)	(1)	(540)	(3)
Reductions for securities which we intend to sell or it is more likely than not that we will be required to sell before recovery of its amortized cost basis	(193)	0	(193)	0
Reductions for amortization resulting from changes in cash flows expected to be collected over the remaining life of the securities	(92)	(91)	(274)	(301)
Balance, end of period	$ 8,223	$ 9,312	$ 8,223	$ 9,312