Mall Activities Mall Activities - Future Minimum Rental Payments Under Non-Cancelable Operating Leases (Details) $ in Millions	Dec. 31, 2018 USD ($)
Operating Leases, Future Minimum Payments Receivable [Abstract]
Operating lease receivables, 2019	$ 457
Operating lease receivables, 2020	366
Operating lease receivables, 2021	269
Operating lease receivables, 2022	184
Operating lease receivables, 2023	80
Operating lease receivables, thereafter	140
Total minimum future rentals	$ 1,496

Future minimum rental payments in aggregate as of the balance sheet date under operating leases.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84164653&loc=d3e41551-112718

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- Definition

Future rental payments receivable within one year of the balance sheet date under an operating lease.

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- Definition

Future rental payments receivable within the fifth year from the balance sheet date under an operating lease.

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- Definition

Future rental payments receivable within the fourth year from the balance sheet date under an operating lease.

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- Definition

Future rental payments receivable within the third year from the balance sheet date under an operating lease.

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- Definition

Future rental payments receivable within the second year from the balance sheet date under an operating lease.

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- Definition

Future minimum lease payments receivable under operating leases for periods greater than five years following the balance sheet date.

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