Accumulated Other Comprehensive Income (Loss) - Changes in Components of Accumulated Other Comprehensive Income, Net of Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017	Mar. 31, 2018
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance			$ 2,021.5
Other comprehensive (loss) income, net of tax			(113.5)
Ending balance	$ 2,183.3		2,183.3
Foreign currency translation loss	25.2	$ (15.0)	128.2	$ (37.1)
Foreign Currency Translation (Losses) Gains
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance			61.2	(86.1)
Other comprehensive (loss) income before reclassifications			(128.1)	37.1
Less: amounts reclassified from AOCI to earnings			0.0	0.0
Other comprehensive (loss) income, net of tax			(128.1)	37.1
Ending balance	(66.9)	(49.0)	(66.9)	(49.0)
Net gain (loss) on long-term transactions			8.4	(2.8)
Gain related to net investment hedges	3.9		3.9
Taxes related to the gain on net investment hedges			0.7
Net Gains (Losses) on Derivatives
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance			(10.7)	5.5
Other comprehensive (loss) income before reclassifications			8.7	(13.2)
Less: amounts reclassified from AOCI to earnings			(6.0)	2.9
Other comprehensive (loss) income, net of tax			14.7	(16.1)
Ending balance	4.0	(10.6)	4.0	(10.6)
Accumulated other comprehensive income, tax provision (benefit)	0.5		0.5		$ (1.4)
Tax benefit of amount reclassified from AOCI			0.9
Other comprehensive income (loss) before reclassifications, tax provision			1.0	2.1
Other Comprehensive (Loss) Income Attributable to MKHL
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance			50.5	(80.6)
Other comprehensive (loss) income before reclassifications			(119.4)	23.9
Less: amounts reclassified from AOCI to earnings			(6.0)	2.9
Other comprehensive (loss) income, net of tax			(113.4)	21.0
Ending balance	(62.9)	(59.6)	(62.9)	(59.6)
Other Comprehensive (Loss) Income Attributable to Noncontrolling Interest
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance			(0.2)	(0.3)
Other comprehensive (loss) income before reclassifications			(0.1)	0.0
Less: amounts reclassified from AOCI to earnings			0.0	0.0
Other comprehensive (loss) income, net of tax			(0.1)	0.0
Ending balance	(0.3)	(0.3)	(0.3)	(0.3)
Total Accumulated Other Comprehensive (Loss) Income
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance			50.3	(80.9)
Other comprehensive (loss) income before reclassifications			(119.5)	23.9
Less: amounts reclassified from AOCI to earnings			(6.0)	2.9
Other comprehensive (loss) income, net of tax			(113.5)	21.0
Ending balance	$ (63.2)	$ (59.9)	(63.2)	$ (59.9)
Jimmy Cho PLC | Foreign Currency Translation (Losses) Gains
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Foreign currency translation loss			$ 105.1