Commitments, Contingencies, Guarantees, and Others - Schedule of Unpaid Principal Balance of Mortgage Loans Originated and Sold to Third Parties Based on Category of Purchaser (Details) (USD $) In Billions, unless otherwise specified	49 Months Ended
	Feb. 28, 2009 Subsidiary	Sep. 30, 2014	Sep. 30, 2014 Subsidiaries	Dec. 31, 2013 Subsidiaries	Sep. 30, 2014 Subsidiaries 2005 to 2008 Year	Sep. 30, 2014 Subsidiaries 2008	Sep. 30, 2014 Subsidiaries 2007	Sep. 30, 2014 Subsidiaries 2006	Sep. 30, 2014 Subsidiaries 2005	Sep. 30, 2014 Subsidiaries Government-sponsored enterprises (“GSEs”)	Dec. 31, 2013 Subsidiaries Government-sponsored enterprises (“GSEs”)	Sep. 30, 2014 Subsidiaries Government-sponsored enterprises (“GSEs”) 2005 to 2008 Year	Sep. 30, 2014 Subsidiaries Government-sponsored enterprises (“GSEs”) 2008	Sep. 30, 2014 Subsidiaries Government-sponsored enterprises (“GSEs”) 2007	Sep. 30, 2014 Subsidiaries Government-sponsored enterprises (“GSEs”) 2006	Sep. 30, 2014 Subsidiaries Government-sponsored enterprises (“GSEs”) 2005	Sep. 30, 2014 Subsidiaries Insured Securitizations	Dec. 31, 2013 Subsidiaries Insured Securitizations	Sep. 30, 2014 Subsidiaries Insured Securitizations 2005 to 2008 Year	Sep. 30, 2014 Subsidiaries Insured Securitizations 2008	Sep. 30, 2014 Subsidiaries Insured Securitizations 2007	Sep. 30, 2014 Subsidiaries Insured Securitizations 2006	Sep. 30, 2014 Subsidiaries Insured Securitizations 2005	Sep. 30, 2014 Subsidiaries Uninsured Securitizations and Other	Dec. 31, 2013 Subsidiaries Uninsured Securitizations and Other	Sep. 30, 2014 Subsidiaries Uninsured Securitizations and Other 2005 to 2008 Year	Sep. 30, 2014 Subsidiaries Uninsured Securitizations and Other 2008	Sep. 30, 2014 Subsidiaries Uninsured Securitizations and Other 2007	Sep. 30, 2014 Subsidiaries Uninsured Securitizations and Other 2006	Sep. 30, 2014 Subsidiaries Uninsured Securitizations and Other 2005	Sep. 30, 2014 Subsidiaries Uninsured Securitizations 2005 to 2008 Year	Sep. 30, 2014 Subsidiaries Private Investors 2005 to 2008 Year	Sep. 30, 2014 Subsidiaries Various Known and Unknown Investors 2005 to 2008 Year
Loss Contingencies [Line Items]
Number of subsidiaries acquired that originated residential mortgage loans	3
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Estimated Unpaid Principal Balance			$ 24	$ 26						$ 3	$ 3						$ 4	$ 5						$ 17	$ 18
Original Principal Balance			111		111	4	21	41	45			11	1	4	3	3			20	0	2	8	10			80	3	15	30	32	48	22	10
Percent covered by bond insurance																			48.00%
Original principal balance, sold to third party with repurchase requests																			16
Original principal balance, sold to third party without repurchase requests																			4
Unpaid principal balance, delinquent 90 days or greater			5
Losses realized by third party		$ 21