Business Developments And Risks And Uncertainties (Narrative) (Detail) $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2018 USD ($) segments $ / shares shares
Business Acquisition [Line Items]
Number of operating segments | segments	3
Warrants outstanding | shares	11,850,000
Warrant exercise price | $ / shares	$ 9.59
Treasury shares issued (in shares) | shares	1,300,000
Zohar [Member]
Business Acquisition [Line Items]
Aggregate claim amount | $	$ 919
Puerto Rico [Member]
Business Acquisition [Line Items]
Claims payments | $	$ 276