Accumulated Other Comprehensive (Loss) Income - Impact and Location of AOCI Reclassifications in Consolidated Statements of Income (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Other Expense									$ (9)	$ (8)	$ (6)
Income tax benefit									(7)	3	(125)
Net (loss) income	$ (19)	$ 10	$ (1)	$ (10)	$ 15	$ 18	$ 4	$ (7)	(20)	30	(67)
Amount Reclassified from of Accumulated Other Comprehensive Income
Defined Benefit Plan Disclosure [Line Items]
Other Expense									(7)	(6)	(5)
Income tax benefit									1	1	1
Net (loss) income									$ (6)	$ (5)	$ (4)