Restructuring and Related Activities - Schedule of Incurred Costs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended	18 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024	Jun. 30, 2025
Restructuring Cost and Reserve [Line Items]
Goodwill impairment		$ 675.3	$ 0.0	$ 675.3
Bedding Products
Restructuring Cost and Reserve [Line Items]
Goodwill impairment		587.2		587.2	$ 0.7
2024 restructuring plan
Restructuring Cost and Reserve [Line Items]
Total restructuring-related costs			8.8		47.8	$ 56.6
2024 restructuring plan \| Other restructuring
Restructuring Cost and Reserve [Line Items]
Total restructuring-related costs	$ 2.4	10.9	7.6	19.4	43.6	51.2
2024 restructuring plan \| Other restructuring \| Bedding Products
Restructuring Cost and Reserve [Line Items]
Total restructuring-related costs	1.2	$ 9.6	4.3	$ 16.6
2024 restructuring plan \| Net cash restructuring and restructuring-related
Restructuring Cost and Reserve [Line Items]
Total restructuring-related costs			7.1		30.3	37.4
2024 restructuring plan \| Net non-cash restructuring and restructuring-related
Restructuring Cost and Reserve [Line Items]
Total restructuring-related costs			0.5		13.3	13.8
2024 restructuring plan \| Goodwill and long-lived asset impairment costs
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	10.0		10.0			10.0
Total restructuring-related costs			1.2		$ 4.2	5.4
Minimum \| 2024 restructuring plan
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	65.0		65.0			65.0
Minimum \| 2024 restructuring plan \| Other restructuring
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	55.0		55.0			55.0
Minimum \| 2024 restructuring plan \| Net cash restructuring and restructuring-related
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	40.0		40.0			40.0
Minimum \| 2024 restructuring plan \| Net non-cash restructuring and restructuring-related
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	15.0		15.0			15.0
Maximum \| 2024 restructuring plan
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	75.0		75.0			75.0
Maximum \| 2024 restructuring plan \| Other restructuring
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	65.0		65.0			65.0
Maximum \| 2024 restructuring plan \| Net cash restructuring and restructuring-related
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	45.0		45.0			45.0
Maximum \| 2024 restructuring plan \| Net non-cash restructuring and restructuring-related
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	$ 20.0		$ 20.0			$ 20.0