COVID-19 Repositioning Costs [Abstract]

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Real estate operating lease ROU asset and other asset impairment charges

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Includes, but is not limited to, one-time termination benefits, termination of an operating lease or other contract, consolidating or closing facilities, and relocating employees, and termination benefits associated with an ongoing benefit arrangement. Excludes expenses associated with special or contractual termination benefits, a discontinued operation or an asset retirement obligation.

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Amount of gain (loss) from sale and disposal of integrated set of activities and assets capable of being conducted and managed for purpose of providing return in form of dividend, lower cost, or other economic benefit to investor, owner, member and participant.

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Amount of other expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses associated with a discontinued operation or an asset retirement obligation.

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Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of expenses for special or contractual termination benefits provided to current employees involuntarily terminated under a benefit arrangement associated exit or disposal activities pursuant to an authorized plan. Excludes expenses related to one-time termination benefits, a discontinued operation or an asset retirement obligation.

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COVID-19 Repositioning Costs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended	12 Months Ended
	Jun. 30, 2020	Sep. 30, 2018	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
COVID-19 Repositioning Costs [Abstract]
Incremental severance costs	$ 150.0	$ 68.4
Real estate operating lease ROU asset and other asset impairment charges	55.8
Other real estate exit costs	47.0	73.5
Dispositions and other repositioning charges	25.1	7.5
Repositioning Costs	277.9	149.4		$ 277.9	$ 0.0	$ 0.0
Net gain on disposition of subsidiaries		$ (178.4)		0.0	$ 0.0	$ (178.4)
Repositioning Liabilities [Roll Forward]
Repositioning Liabilities, Opening balance			$ 197.0
Repositioning Liabilities, Payments			(113.2)
Repositioning Liabilities, December 31, 2020	$ 197.0		$ 83.8	$ 83.8