Income Taxes - Schedule of Expiration Periods of Deferred Tax Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Tax Credit Carryforward [Line Items]
Tax loss carryforwards	$ 1,411
Tax credit carryforwards	26	$ 27
Other	1,351
Valuation allowance	(1,778)	(1,684)	$ (1,927)	$ (1,755)
Total	1,010	$ 872
Expires Within 10 Years [Member]
Tax Credit Carryforward [Line Items]
Tax loss carryforwards	333
Tax credit carryforwards	17
Valuation allowance	(350)
Expires Within 11-20 Years [Member]
Tax Credit Carryforward [Line Items]
Tax loss carryforwards	323
Tax credit carryforwards	9
Valuation allowance	(318)
Total	14
No Expiration [Member]
Tax Credit Carryforward [Line Items]
Tax loss carryforwards	755
Other	170
Valuation allowance	(300)
Total	625
Other [Member]
Tax Credit Carryforward [Line Items]
Other	1,181
Valuation allowance	(810)
Total	$ 371