Schedule III - Real Estate and Accumulated Depreciation - Change in Accumulated Depreciation (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Real Estate And Accumulated Depreciation Disclosure [Abstract]
Balance at beginning of period	$ 2,038	$ 2,011	$ 2,004
Additions during period:
Depreciation expense	294	256	268
Deductions during period:
Transfers to assets held for sale		(24)
Dispositions, including casualty losses	(89)	(206)	(262)
Foreign exchange effect	(2)	1	1
Balance at end of period	$ 2,241	$ 2,038	$ 2,011