Commitments and Contingencies (Lease Disclosures) (Detail) - USD ($) $ in Millions	Dec. 31, 2019	Jan. 01, 2019
Lessee Disclosure [Abstract]
Operating lease right of use asset	$ 21	$ 23
Operating lease liability	$ 21
Operating lease weighted average remaining lease term	8 years 2 months 12 days
Operating lease weighted average discount rate percent	7.50%
Operating leases future minimum payments due	$ 32