Income Taxes - Deferred Income Tax Assets and Liabilities (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Income Tax Disclosure [Abstract]
Net operating loss carryforward	$ 205	[1]	$ 254	[1]
Market value difference of loan portfolio	349		117
Purchase accounting adjustments	37		56
Accruals	157		131
Income tax benefits from uncertain tax positions	31		31
Other	81		101
Total deferred tax assets before valuation allowance	860		690
Less: valuation allowance	(57)		(104)
Deferred income taxes	803		586
Capitalized direct loan origination costs	22		18
Fee income	21		32
Depreciable assets	300		153
Intangible assets	35		40
Accrued commissions	41		28
Deferred acquisition costs/revenue	50		30
Other	13		13
Total deferred tax liabilities	482		314
Net deferred tax asset	$ 321		$ 272

[1] Includes tax-effected operating losses of $58 million expiring through 2035 and $147 million that may be carried forward indefinitely at December 31, 2014.