Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
	Aug. 09, 2018	Oct. 03, 2021	Sep. 27, 2020	Oct. 03, 2021	Sep. 27, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized gain (loss) on investments		$ (86.3)	$ 155.4	$ (48.0)	$ 274.4
Enphase Shares
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Shares issuable to the company at closing of agreement (in shares)	7,500,000
Investment shares sold (in shares)		1,000,000	1,000,000	1,000,000	2,000,000
Proceeds from sale of equity investment		$ 177.8	$ 73.3	$ 177.8	$ 117.0