Fair value measurement (Tables)

3 Months Ended

Mar. 28, 2020

Fair Value Disclosures [Abstract]

Schedule of carrying amount and fair value of debt

The carrying amount and fair value of our debt are set out below:

	As of March 28, 2020				As of December 28, 2019
(dollars in millions)	Carrying amount		Fair value		Carrying amount		Fair value
Current	$	54.9	$	44.8	$	46.1	$	45.9
Non-current	2,901.9		2,490.5		2,912.3		2,946.8
	$	2,956.8	$	2,535.3	$	2,958.4	$	2,992.7

Schedule of assets and liabilities measured at fair value on a recurring basis

The following table categorizes the assets and liabilities that are measured at fair value on a recurring basis:

(dollars in millions)	Quoted prices in active markets (Level 1)		Significant observable inputs (Level 2)		Total
As of March 28, 2020
Equity investments	$	1.0	$	—	$	1.0
Derivative assets	$	—	$	2.9	$	2.9
Derivative liabilities	$	—	$	(71.2)	$	(71.2)
As of December 28, 2019
Equity investments	$	1.1	$	—	$	1.1
Derivative assets	$	—	$	5.4	$	5.4
Derivative liabilities	$	—	$	(60.9)	$	(60.9)