Commitments and Contingencies (Lease Disclosures) (Detail) $ in Millions	Mar. 31, 2020 USD ($)
Lessee Disclosure [Abstract]
Operating lease right of use asset	$ 21
Operating lease liability	$ 21
Operating lease weighted average remaining lease term	8 years 3 months 18 days
Operating lease weighted average discount rate percent	7.50%
Operating leases future minimum payments due	$ 31