Other Assets - Intangible Assets Disclosure (Detail) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross carrying value	$ 2,217	$ 1,753
Accumulated amortization	(1,576)	(1,429)
Net carrying value	641	324
Customer Lists [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying value	1,427	1,117
Accumulated amortization	(1,044)	(970)
Net carrying value	383	147
Acquired leases and other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying value	790	636
Accumulated amortization	(532)	(459)
Net carrying value	$ 258	$ 177