Reconciliation of Carrying Amounts of Real Estate Investments (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
Beginning Balance	$ 15,642	$ 15,370	$ 15,546
Additions:
Acquisitions	1,563		625
Capital expenditures and transfers from construction-in-progress	231	446	332
Deductions:
Dispositions and other	(954)	(174)	(1,127)
Assets held for sale	(444)
Impairments	(92)		(6)
Ending Balance	$ 15,946	$ 15,642	$ 15,370