Income Taxes - Net Deferred Tax Position (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Allowance for credit losses	$ 131	$ 166
Interests in real estate mortgage investment conduits	182	175
Unrealized losses on investment securities	164	96
Capitalized costs	680	724
Fair value adjustments	0	26
Other	350	385
Total deferred tax assets	1,507	1,572
Valuation allowance	(6)	(6)
Total deferred tax assets, net of valuation allowance	1,501	1,566
Less deferred tax liabilities:
Fair value adjustments	75	0
Amortization of intangible assets	18	18
Other	22	8
Total deferred tax liabilities	115	26
Net deferred tax asset	$ 1,386	$ 1,540