Derivatives and Hedging Activities - Schedule of Fair Value of Derivative Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Derivatives not designated as hedging instruments:
Gross position	$ 8.1	$ 9.2
Total Derivative Liabilities	(53.9)	(6.6)
Net Derivatives	(45.8)	2.6
Foreign currency forward contracts
Derivatives not designated as hedging instruments:
Gross position	8.1	6.0
Total Derivative Liabilities	(2.3)	(6.6)
Cross-currency swaps
Derivatives not designated as hedging instruments:
Gross position	0.0	3.2
Total Derivative Liabilities	(51.6)	0.0
Non-Designated as Hedging Instruments
Derivatives not designated as hedging instruments:
Gross position	6.7	1.2
Total Derivative Liabilities	(1.7)	(6.2)
Net Derivatives	5.0	(5.0)
Non-Designated as Hedging Instruments \| Foreign currency forward contracts
Derivatives not designated as hedging instruments:
Gross position	6.7	1.2
Total Derivative Liabilities	(1.7)	(6.2)
Non-Designated as Hedging Instruments \| Cross-currency swaps
Derivatives not designated as hedging instruments:
Gross position	0.0	0.0
Total Derivative Liabilities	0.0	0.0
Cash Flow Hedge \| Cash Flow Hedge
Derivatives not designated as hedging instruments:
Gross position	1.4	4.8
Total Derivative Liabilities	(0.6)	(0.4)
Net Derivatives	0.8	4.4
Cash Flow Hedge \| Cash Flow Hedge \| Foreign currency forward contracts
Derivatives not designated as hedging instruments:
Gross position	1.4	4.8
Total Derivative Liabilities	(0.6)	(0.4)
Cash Flow Hedge \| Cash Flow Hedge \| Cross-currency swaps
Derivatives not designated as hedging instruments:
Gross position	0.0	0.0
Total Derivative Liabilities	0.0	0.0
Net Investment Hedge
Derivatives not designated as hedging instruments:
Gross position	0.0	3.2
Total Derivative Liabilities	(51.6)	0.0
Net Derivatives	(51.6)	3.2
Net Investment Hedge \| Foreign currency forward contracts
Derivatives not designated as hedging instruments:
Gross position	0.0	0.0
Total Derivative Liabilities	0.0	0.0
Net Investment Hedge \| Cross-currency swaps
Derivatives not designated as hedging instruments:
Gross position	0.0	3.2
Total Derivative Liabilities	$ (51.6)	$ 0.0

SEALED AIR CORP/DE 10-Q