Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Deferred income tax assets:
Lease and rents	$ 5,742.0	$ 5,731.0
Inventory	80.0	23.0
Employee benefits	238.0	191.0
Bad debts and other allowances	395.0	294.0
Retirement benefits	0.0	47.0
Net operating loss and capital loss carryforwards	568.0	480.0
Deferred income	43.0	36.0
Insurance reserves	489.0	430.0
Payroll tax deferral	173.0	0.0
Other	500.0	451.0
Valuation allowance	(454.0)	(374.0)
Total deferred income tax assets	7,774.0	7,309.0
Deferred income tax liabilities:
Retirement benefits	(29.0)	0.0
Investments	(421.0)	(289.0)
Lease and rents	(5,368.0)	(5,464.0)
Depreciation and amortization	(8,750.0)	(8,850.0)
Total deferred income tax liabilities	(14,568.0)	(14,603.0)
Net deferred income tax liabilities	$ (6,794.0)	$ (7,294.0)

Deferred Tax Assets, Payroll Tax Deferral

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Deferred Tax Assets, Tax Deferred Expense, Reserves And Accruals, Bad Debts And Other Allowances

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Deferred Tax Liabilities, Depreciation and Amortization - Amount of deferred tax liability attributable to taxable temporary differences from depreciation and amortization

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Deferred Tax Liabilities, Retirement Benefits

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Amount of deferred tax liability attributable to taxable temporary differences.

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Amount of deferred tax liability attributable to taxable temporary differences from investments (excludes investments in subsidiaries and equity method investments).

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Amount of deferred tax liability attributable to taxable temporary differences from leasing arrangements.

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