Loss And Loss Adjustment Expense Reserves (Schedule Of Insurance Loss Recoverable) (Detail) - Insurance Loss Recoverable [Member] - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019		Dec. 31, 2018
Roll forward of Insurance Loss Recoverable [Line Items]
Gross Reserve beginning balance, Insurance loss recoverable		$ 1,595		$ 545
Collections for Cases		(148)		(56)
Accretion of Recoveries		35		25
Changes in Discount Rates		70		(13)
Changes in Assumptions		105	[1]	1,096	[2]
Other	[3]	37		(2)
Gross Reserve ending balance, Insurance loss recoverable		$ 1,694		$ 1,595

[1] Includes amounts related to paid claims and LAE that are expected to be recovered in the future.

[2] Includes amounts which have been paid and are expected to be recovered in the future.

[3] Primarily changes in amount and timing of collections.