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	3 Months Ended	49 Months Ended
	Mar. 31, 2017 USD ($)	Feb. 28, 2009 Subsidiary	Dec. 31, 2016 USD ($)
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
Increase (Decrease) In Unresolved Repurchase Claims Face Amount	716
Subsidiaries
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Estimated Unpaid Principal Balance	16,000		$ 17,000
Unpaid principal balance, delinquent 90 days or greater	3,000
Unresolved Repurchase Claims, Face Amount	653		1,369
Subsidiaries | 2005 to 2008 Year
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Original Principal Balance	111,000
Subsidiaries | Government-sponsored enterprises (“GSEs”)
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Estimated Unpaid Principal Balance	2,000		2,000
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 | Insured Securitizations
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Estimated Unpaid Principal Balance	3,000		3,000
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 | Uninsured Securitizations and Other
Mortgage Loans on Real Estate, Sold to Third Party [Abstract]
Estimated Unpaid Principal Balance	11,000		12,000
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 | 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	$ 1,400		$ 1,500