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) $ in Millions	49 Months Ended
	Feb. 28, 2009 Subsidiary	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Loss Contingencies [Line Items]
Number of subsidiaries acquired that originated residential mortgage loans | Subsidiary	3
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Losses realized by third party		$ 23,000
Subsidiaries
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Estimated Unpaid Principal Balance		17,000	$ 20,000
Unpaid principal balance, delinquent 90 days or greater		3,000
Unresolved Repurchase Claims, Face Amount		1,369	1,350	$ 2,512
Subsidiaries | 2005 to 2008 Year
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		111,000
Subsidiaries | 2008
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		4,000
Subsidiaries | 2007
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		21,000
Subsidiaries | 2006
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		41,000
Subsidiaries | 2005
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		45,000
Subsidiaries | Government-sponsored enterprises (“GSEs”)
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Estimated Unpaid Principal Balance		2,000	2,000
Unresolved Repurchase Claims, Face Amount		8	1	16
Subsidiaries | Government-sponsored enterprises (“GSEs”) | 2005 to 2008 Year
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		11,000
Subsidiaries | Government-sponsored enterprises (“GSEs”) | 2008
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		1,000
Subsidiaries | Government-sponsored enterprises (“GSEs”) | 2007
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		4,000
Subsidiaries | Government-sponsored enterprises (“GSEs”) | 2006
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		3,000
Subsidiaries | Government-sponsored enterprises (“GSEs”) | 2005
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		3,000
Subsidiaries | Insured Securitizations
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Estimated Unpaid Principal Balance		3,000	4,000
Unresolved Repurchase Claims, Face Amount		535	534	649
Subsidiaries | Insured Securitizations | 2005 to 2008 Year
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		$ 20,000
Percent covered by bond insurance		48.00%
Original principal balance, sold to third party with repurchase requests		$ 16,000
Original principal balance, sold to third party without repurchase requests		4,000
Subsidiaries | Insured Securitizations | 2008
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		0
Subsidiaries | Insured Securitizations | 2007
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		2,000
Subsidiaries | Insured Securitizations | 2006
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		8,000
Subsidiaries | Insured Securitizations | 2005
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		10,000
Subsidiaries | Uninsured Securitizations and Other
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Estimated Unpaid Principal Balance		12,000	14,000
Unresolved Repurchase Claims, Face Amount		826	815	$ 1,847
Subsidiaries | Uninsured Securitizations and Other | 2005 to 2008 Year
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		80,000
Subsidiaries | Uninsured Securitizations and Other | 2008
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		3,000
Subsidiaries | Uninsured Securitizations and Other | 2007
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		15,000
Subsidiaries | Uninsured Securitizations and Other | 2006
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		30,000
Subsidiaries | Uninsured Securitizations and Other | 2005
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		32,000
Subsidiaries | Uninsured Securitizations | 2005 to 2008 Year
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		48,000
Subsidiaries | Private Investors | 2005 to 2008 Year
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		22,000
Subsidiaries | Various Known and Unknown Investors | 2005 to 2008 Year
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance		10,000
Representation and Warranty Liability [Member] | Subsidiaries
Loss Contingencies [Line Items]
Loss Contingency, Range of Possible Loss, Portion Not Accrued		$ 1,500	$ 1,600