Income Taxes - Net Deferred Tax Position (Detail) - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015
Deferred Tax Assets:
Receivables held for sale		$ 387	$ 541
Federal and state unused tax benefit carryforwards		2,577	1,719
Market value adjustment related to derivatives and long-term debt carried at fair value		16	275
Interests in Real Estate Mortgage Investment Conduits	[1]	380	345
Accrued expenses not currently deductible		78	480
Other		204	379
Total deferred tax assets		3,642	3,739
Valuation allowance		(690)	(707)
Total deferred tax assets net of valuation allowance		2,952	3,032
Deferred Tax Liabilities:
Fee income		26	54
Other		29	55
Total deferred tax liabilities		55	109
Net deferred tax assets		$ 2,897	$ 2,923

[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.