Financial Instruments and Hedging Activities (Fair Values of Derivative Instruments Included on Consolidated Balance Sheet) (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Derivatives, Fair Value [Line Items]
Asset Derivatives Fair Value	$ 186.0	$ 334.0
Liability Derivatives Fair Value	(123.0)	(41.0)
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Asset Derivatives Fair Value	40.0	199.0
Liability Derivatives Fair Value	(123.0)	(41.0)
Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Asset Derivatives Fair Value	146.0	135.0
Liability Derivatives Fair Value	0.0	0.0
Foreign Exchange [Member] \| Prepaid Expenses and Other Current Assets [Member] \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Asset Derivatives Fair Value	33.0	125.0
Foreign Exchange [Member] \| Prepaid Expenses and Other Current Assets [Member] \| Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Asset Derivatives Fair Value	0.0	0.0
Foreign Exchange [Member] \| Accrued Expenses And Other Current Liabilities [Member] \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Liability Derivatives Fair Value	(62.0)	(1.0)
Foreign Exchange [Member] \| Accrued Expenses And Other Current Liabilities [Member] \| Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Liability Derivatives Fair Value	0.0	0.0
Foreign Exchange [Member] \| Other Assets [Member] \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Asset Derivatives Fair Value	7.0	40.0
Foreign Exchange [Member] \| Other long-term liabilities \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Liability Derivatives Fair Value	(29.0)	0.0
Equity [Member] \| Prepaid Expenses and Other Current Assets [Member] \| Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Asset Derivatives Fair Value	146.0	135.0
Equity [Member] \| Accrued Expenses And Other Current Liabilities [Member] \| Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Liability Derivatives Fair Value	0.0	0.0
Interest Rate Contract [Member] \| Prepaid Expenses and Other Current Assets [Member] \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Asset Derivatives Fair Value	0.0	34.0
Interest Rate Contract [Member] \| Accrued Expenses And Other Current Liabilities [Member] \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Liability Derivatives Fair Value	(5.0)	(6.0)
Interest Rate Contract [Member] \| Other Assets [Member] \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Asset Derivatives Fair Value	0.0	0.0
Interest Rate Contract [Member] \| Other long-term liabilities \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Liability Derivatives Fair Value	$ (27.0)	$ (34.0)

MCDONALDS CORP 10-Q