Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
	Aug. 09, 2018	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized gain (loss) on investments		$ 83.0	$ 71.1	$ 38.3	$ 119.0
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
Proceeds from sale of equity investment					$ 43.7