Revenue from Contracts with Customers - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation Of Revenue [Line Items]
Uncollected amounts receivable	$ 62	$ 56
Accrued interest and other liabilities [Member]
Disaggregation Of Revenue [Line Items]
Deferred revenue	43	43
ASU 2014-09 [Member]
Disaggregation Of Revenue [Line Items]
Expense recognized on credit card rewards in other costs of operations	$ 25	$ 14	$ 13