Investments in Securities Other-than-temporary Impairments 2 (Details) - Available-for-sale securities [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance, beginning of period	$ 2,293	$ 2,744	$ 2,421	$ 5,260
Additions for the credit component on debt securities for which OTTI was previously recognized	2	0	6	4
Reductions for securities no longer in portfolio at period end	(10)	(72)	(103)	(1,165)
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	(31)	(70)	(31)	(1,439)
Reductions for amortization resulting from changes in cash flows expected to be collected over the remaining life of the securities	(35)	(45)	(74)	(103)
Balance, end of period	$ 2,219	$ 2,557	$ 2,219	$ 2,557