Fair Value Measurements - Fair Values of Note Payable and Long-Term Debt (Detail) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of note payable	$ 37	$ 32
Total	1,049	975
Loans and Leases Receivable, Net Amount	$ 76	$ 71
Senior Debentures 6.900 % Due 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate	6.90%	6.90%
Debt instrument, year of maturity	2028	2028
Fair value of senior debt	$ 34	$ 32
Senior Debentures 6.920 % Due 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate	6.92%	6.92%
Debt instrument, year of maturity	2028	2028
Fair value of senior debt	$ 502	$ 471
Senior Notes 6.125 % Due 2034
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate	6.125%	6.125%
Debt instrument, year of maturity	2034	2034
Fair value of senior debt	$ 476	$ 440
Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of note payable	0	0
Total	0	0
Quoted prices in active markets for identical assets (Level 1) \| Senior Debentures 6.900 % Due 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of senior debt	0	0
Quoted prices in active markets for identical assets (Level 1) \| Senior Debentures 6.920 % Due 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of senior debt	0	0
Quoted prices in active markets for identical assets (Level 1) \| Senior Notes 6.125 % Due 2034
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of senior debt	0	0
Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of note payable	37	32
Total	1,049	975
Significant other observable inputs (Level 2) \| Senior Debentures 6.900 % Due 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of senior debt	34	32
Significant other observable inputs (Level 2) \| Senior Debentures 6.920 % Due 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of senior debt	502	471
Significant other observable inputs (Level 2) \| Senior Notes 6.125 % Due 2034
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of senior debt	476	440
Significant unobservable inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of note payable	0	0
Total	0	0
Significant unobservable inputs (Level 3) \| Senior Debentures 6.900 % Due 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of senior debt	0	0
Significant unobservable inputs (Level 3) \| Senior Debentures 6.920 % Due 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of senior debt	0	0
Significant unobservable inputs (Level 3) \| Senior Notes 6.125 % Due 2034
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of senior debt	0	0
Life Policy Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans and Leases Receivable, Net Amount	$ 33	$ 33

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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Fair value portion of notes payable.

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