Income Taxes - Significant Portions of Deferred Tax Liabilities and Deferred Tax Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Schedule of Deferred Income Tax Assets and Liabilities [Line Items]
Deferred Tax Assets, Net of Valuation Allowance	$ 106	$ 128
Deferred tax assets:
Net operating loss and capital carryforward	786	764
Loss reserves	180	218
Deferred Tax Assets, Operating Loss Carryforwards, State and Local	7	0
Deferred Tax Assets, Debentures	7	22
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Compensation	8	9
Other	4	5
Sub total deferred tax assets	993	1,019
Valuation allowance	886	891
Insurance intangible	67	78
Variable interest entities	15	13
Investments	14	22
Unearned premiums and credit fees	32	32
Other	6	7
Deferred Tax Liabilities, Gross	134	152
Deferred Tax Liabilities, Net	$ 28	$ 24