Investments in Securities Other-than-temporary Impairments 2 (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
Schedule of Available-for-sale Securities [Line Items]
Net other-than-temporary impairments	$ 27	[1]	$ 38	$ 42	[1]	$ 701
Net other-than-temporary impairments recognized in earnings related to securities as we had the intent to sell the related securities before recovery of their amortized cost basis	26			26
Alt-A private-label securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Net other-than-temporary impairments	23		6	29		361
Subprime private-label securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Net other-than-temporary impairments	2		21	5		324
Other mortgage-related securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Net other-than-temporary impairments	$ 2		$ 11	$ 8		$ 16

[1] Includes $26 million of other-than-temporary impairments recognized in earnings for the three and nine months ended September 30, 2013, as we had the intent to sell the related securities before recovery of their amortized cost basis.