Loss And Loss Adjustment Expense Reserves (Schedule Of Insurance Loss Recoverable) (Detail) - Insurance Loss Recoverable [Member] $ in Millions	9 Months Ended
Sep. 30, 2020 USD ($)
Roll forward of Insurance Loss Recoverable [Line Items]
Gross Reserve beginning balance, Insurance loss recoverable	$ 1,694
Collections for Cases	(35)
Accretion of Recoveries	11
Changes in Discount Rates	152
Changes in Assumptions	(21)
Other	(3)
Gross Reserve ending balance, Insurance loss recoverable	$ 1,798

Cash receipts related to recoveries of previously paid claims

No definition available.

Carrying amount as of the balance sheet date of paid insurance policy claims and LAE expense expected to be recovered.

No definition available.

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Insurance Loss Recoverable And Changes In Recoveries Of Unpaid Losses Accretion Of Recoveries

No definition available.

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Insurance Loss Recoverable And Changes In Recoveries Of Unpaid Losses Change In Assumptions

No definition available.

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Insurance Loss Recoverable And Changes In Recoveries Of Unpaid Losses Change In Discount Rate

No definition available.

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Changes in the timing and amount of net collections on financial guarantee contracts.

No definition available.

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Roll forward of Insurance Loss Recoverable [Line Items]

No definition available.

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