DESCRIPTION OF BUSINESS - COVID-19 Update (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Unusual or Infrequent Item, or Both [Line Items]
Impairment of real estate	$ 78,500,000	$ 12,200,000
Commercial paper	215,000,000		$ 0
Revolving Credit Facility | Unsecured revolving credit facility (1)
Unusual or Infrequent Item, or Both [Line Items]
Maximum borrowing capacity	$ 2,750,000,000		$ 3,000,000,000.0