Recent Accounting Pronouncements (Narrative) (Detail) - USD ($) $ in Millions		9 Months Ended
	Jan. 01, 2020	Sep. 30, 2019	Dec. 31, 2019	Jan. 01, 2019
Operating lease right of use asset			$ 21	$ 23
Accounting Standards Update 2016-13 [Member] | Subsequent Event [Member]
Cumulative-effect adjustment, net of tax	$ 42
Accounting Standards Update 2019-12 [Member]
Intraperiod allocations		$ 29