Investments in Securities Other-than-temporary Impairments 3 (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 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)	$ (85)	$ 403	$ (118)	$ 387
Available-for-sale Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance, beginning of period	9,136	8,870	9,214	8,915
Additions for the credit component on debt securities for which OTTI was not previously recognized	2	2	7	2
Additions for the credit component on debt securities for which OTTI was previously recognized	4	597	8	661
Reductions for securities no longer in portfolio at period end	(81)	(2)	(83)	(2)
Reductions for amortization resulting from changes in cash flows expected to be collected over the remaining life of the securities	(97)	(101)	(182)	(210)
Balance, end of period	$ 8,964	$ 9,366	$ 8,964	$ 9,366