Commitments, Contingencies, Guarantees, and Others - Schedule of Allocation of Representation and Warranty Reserves (Details) $ in Millions	3 Months Ended		9 Months Ended		49 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Feb. 28, 2009 Subsidiary	Jun. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)	Jun. 30, 2014 USD ($)	Dec. 31, 2013 USD ($)
Loss Contingencies [Line Items]
Number of subsidiaries acquired that originated residential mortgage loans | Subsidiary					3
Subsidiaries | 2005 to 2008 Year
Loss Contingencies [Line Items]
Loans sold 2005 to 2008	$ 111,000		$ 111,000
Subsidiaries | GSEs and Active Insured Securitizations
Loss Contingencies [Line Items]
Loans sold 2005 to 2008	27,000		27,000
Subsidiaries | Inactive Insured Securitizations and Others
Loss Contingencies [Line Items]
Loans sold 2005 to 2008	84,000		84,000
Subsidiaries | Government-sponsored enterprises (“GSEs”) | 2005 to 2008 Year
Loss Contingencies [Line Items]
Loans sold 2005 to 2008	11,000		11,000
Subsidiaries | Insured Securitizations | 2005 to 2008 Year
Loss Contingencies [Line Items]
Loans sold 2005 to 2008	20,000		20,000
Original principal balance, sold to third party with repurchase requests	16,000		16,000
Original principal balance, sold to third party without repurchase requests	4,000		4,000
Subsidiaries | Uninsured Securitizations | 2005 to 2008 Year
Loss Contingencies [Line Items]
Loans sold 2005 to 2008	48,000		48,000
Subsidiaries | Private Investors | 2005 to 2008 Year
Loss Contingencies [Line Items]
Loans sold 2005 to 2008	22,000		22,000
Subsidiaries | Representation and Warranty Liability [Member]
Loss Contingencies [Line Items]
Reserve liability	632	$ 1,080	632	$ 1,080		$ 636	$ 731	$ 1,012	$ 1,172
Loss Contingency Accrual, Provision	(4)	70	(58)	19
Loss Contingency, Range of Possible Loss, Portion Not Accrued	1,600		1,600				2,100
Net realized losses	0	$ (2)	(41)	$ (111)
Subsidiaries | Representation and Warranty Liability [Member] | GSEs and Active Insured Securitizations
Loss Contingencies [Line Items]
Reserve liability	484		484				499
Subsidiaries | Representation and Warranty Liability [Member] | Inactive Insured Securitizations and Others
Loss Contingencies [Line Items]
Reserve liability	$ 148		$ 148				$ 232