The aggregate net change in the difference between the fair value and the carrying value, or in the comparative fair values, of marketable securities categorized as trading held at each balance sheet date, that was included in earnings for the period, which may have arisen from (a) securities classified as trading, (b) the unrealized holding gain (loss) on held-to-maturity securities transferred to the trading security category, and (c) the cumulative unrealized gain (loss) which was included in other comprehensive income (a separate component of shareholders' equity) on available-for-sale securities transferred to trading securities during the period and/or any unrealized gains or losses on investments that are separately or otherwise not categorized as trading or available-for-sale.

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Investments in and Advances to Unconsolidated Affiliates - Mervyns I & II - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended	12 Months Ended
	Dec. 31, 2020	Jun. 30, 2020	Jun. 30, 2021	Dec. 31, 2020
Mervyns II
Schedule Of Equity Method Investments [Line Items]
Realized gain on investment	$ 0.4	$ 22.8
Cost method investments effective ownership, shares			4.1
Cost method investments effective ownership interest			1.00%
Unrealized gain on investment		$ 64.9	$ 8.6
Albertson
Schedule Of Equity Method Investments [Line Items]
Unrealized gain on investment				$ 7.5