Income Taxes - Net Deferred Tax Position (Details) - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Allowance for credit losses		$ 392	$ 346
Employee benefit accruals		108	124
Accrued expenses		110	79
Interests in real estate mortgage investment conduits	[1]	548	561
Unrealized losses on investment securities		275	140
Partnerships		113	104
Other		360	360
Total deferred tax assets		1,906	1,714
Valuation allowance		(6)	(6)
Total deferred tax assets, net of valuation allowance		1,900	1,708
Less deferred tax liabilities:
Fair value adjustments		48	137
Mortgage servicing rights		0	52
Other		49	45
Total deferred tax liabilities		97	234
Net deferred tax asset		$ 1,803	$ 1,474

[1] Real estate mortgage investment conduits ("REMICs") are investment vehicles that hold commercial and residential mortgages in trust and issue securities representing an undivided interest in these mortgages. HSBC Bank USA holds portfolios of noneconomic residual interests in a number of REMICs. This item represents tax basis in such interests which has accumulated as a result of tax rules requiring the recognition of income related to such noneconomic residuals.