Income Taxes - Significant Portions of Deferred Tax Liabilities and Deferred Tax Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Schedule of Deferred Income Tax Assets and Liabilities [Line Items]
Deferred Tax Assets, Net of Valuation Allowance	$ 151	$ 212
Deferred tax assets:
Net operating loss and capital carryforward	742	719
Loss reserves	148	227
Deferred Tax Assets, Debentures	29	23
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Compensation	7	10
Other	1	2
Sub total deferred tax assets	927	980
Valuation allowance	777	768
Insurance intangible	90	151
Variable interest entities	12	19
Investments	32	26
Unearned premiums and credit fees	42	48
Other	8	8
Deferred Tax Liabilities, Gross, Noncurrent	183	252
Deferred Tax Liabilities, Net	$ 32	$ 40