Segment Reporting - Net Revenues by Brand and Entertainment Segment (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 28, 2021	Mar. 29, 2020
Revenue from External Customer [Line Items]
Net revenues	$ 1,114.8	$ 1,105.6
Franchise Brands
Revenue from External Customer [Line Items]
Net revenues	491.5	396.5
Partner Brands
Revenue from External Customer [Line Items]
Net revenues	188.0	182.3
Hasbro Gaming
Revenue from External Customer [Line Items]
Net revenues	136.3	140.1
Emerging Brands
Revenue from External Customer [Line Items]
Net revenues	104.7	94.2
Entertainment
Revenue from External Customer [Line Items]
Net revenues	194.3	292.5
Gaming including Magic the Gathering and Monopoly
Revenue from External Customer [Line Items]
Net revenues	365.3	340.5
Entertainment
Revenue from External Customer [Line Items]
Net revenues	218.7	322.5
Entertainment | Film & TV
Revenue from External Customer [Line Items]
Net revenues	166.4	264.0
Entertainment | Family Brands
Revenue from External Customer [Line Items]
Net revenues	18.8	25.9
Entertainment | Music and Other
Revenue from External Customer [Line Items]
Net revenues	$ 33.5	$ 32.6