Income Taxes - Net Deferred Tax Position (Detail) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014
Deferred Tax Assets:
Credit loss reserves		$ 144	$ 881
Receivables held for sale		541	0
Federal and state unused tax benefit carryforwards		1,719	1,335
Market value adjustment related to derivatives and long-term debt carried at fair value		275	449
Interests in Real Estate Mortgage Investment Conduits	[1]	345	326
Accrued expenses not currently deductible		480	191
Other		235	280
Total deferred tax assets		3,739	3,462
Valuation allowance		(707)	(878)
Total deferred tax assets net of valuation allowance		3,032	2,584
Deferred Tax Liabilities:
Fee income		54	74
Other		55	66
Total deferred tax liabilities		109	140
Net deferred tax assets		$ 2,923	$ 2,444

[1] Real Estate Mortgage Investment Conduits ("REMIC") are investment vehicles that hold commercial and residential mortgages in trust and issue securities representing an undivided interest in these mortgages. We hold portfolios of noneconomic residual interests in a number of REMICs through one of our subsidiaries. This item represents the tax basis in such interests which has accumulated as a result of tax rules requiring the recognition of income related to such noneconomic residuals.