Other Assets - Intangible Assets Disclosure (Detail) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross carrying value	$ 2,219	$ 2,217
Accumulated amortization	(1,605)	(1,576)
Net carrying value	614	641
Customer Lists [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying value	1,427	1,427
Accumulated amortization	(1,055)	(1,044)
Net carrying value	372	383
Acquired leases and other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying value	792	790
Accumulated amortization	(550)	(532)
Net carrying value	$ 242	$ 258