Fair Values of Deferred Annuities, Structured Settlements and Other Items (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of life insurance liabilities	$ 1,069
Deferred Annuities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of life insurance liabilities	845	794
Structured Settlements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of life insurance liabilities	224	208
Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of life insurance liabilities	224
Fair Value, Inputs, Level 2 | Structured Settlements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of life insurance liabilities	224
Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of life insurance liabilities	845
Fair Value, Inputs, Level 3 | Deferred Annuities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of life insurance liabilities	$ 845