Investments in Securities Other-than-temporary Impairments 2 (Details) (Available-for-sale securities [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Available-for-sale securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance, beginning of period	$ 5,260	$ 7,904
Additions for the credit component on debt securities for which OTTI was not previously recognized	0	1
Additions for the credit component on debt securities for which OTTI was previously recognized	4	39
Reductions for securities no longer in portfolio at period end	(1,093)	(53)
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 amortized cost basis	(1,369)	(698)
Reductions for amortization resulting from changes in cash flows expected to be collected over the remaining life of the securities	(58)	(97)
Balance, end of period	$ 2,744	$ 7,096