Investments in and Advances to Unconsolidated Affiliates - Mervyns I & II - Additional Information (Details) shares in Millions, $ in Millions	9 Months Ended	177 Months Ended
Sep. 30, 2020 USD ($) shares	Sep. 30, 2020 USD ($) shares
Mervyns II
Schedule of Equity Method Investments [Line Items]
Cost method investment, ownership percentage	28.30%	28.30%
Realized gain on investment	$ 23.2
Cost method investments effective ownership, shares \| shares	4.1	4.1
Cost method investments effective ownership interest	1.00%	1.00%
Unrealized gain on investment	$ 64.9
Albertson
Schedule of Equity Method Investments [Line Items]
Cost method investment, ownership percentage	36.67%	36.67%
Albertson \| Mervyns II
Schedule of Equity Method Investments [Line Items]
Unrealized gain on investment	$ 7.9
Related party revenue		$ 110.0

Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07.1(c))
-URI http://asc.fasb.org/extlink&oid=116637345&loc=SL114874292-224272

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(e))
-URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227

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Balance Type:	credit
Period Type:	duration