Revenue Recognition Disaggregation of Revenue by type of activity and reporting segment (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Inter-segment revenue elimination									$ (10.2)	$ (13.6)	$ (21.8)
Net revenue	$ 947.6	$ 760.6	$ 721.4	$ 664.7	$ 725.7	$ 617.5	$ 623.0	$ 551.8	3,094.3	2,518.0	2,463.4
Softgel and Oral Technologies [Member]
Disaggregation of Revenue [Line Items]
Net revenue									1,062.0	1,039.2	1,114.5
Softgel and Oral Technologies [Member] | Manufacturing & Commercial Product Supply [Member]
Disaggregation of Revenue [Line Items]
Net revenue									955.4	944.6
Softgel and Oral Technologies [Member] | Development Services [Member]
Disaggregation of Revenue [Line Items]
Net revenue									106.6	94.6
Softgel and Oral Technologies [Member] | Clinical Supply Services [Member]
Disaggregation of Revenue [Line Items]
Net revenue									0.0	0.0
Biologics [Member]
Disaggregation of Revenue [Line Items]
Net revenue									1,021.6	573.3	437.0
Biologics [Member] | Manufacturing & Commercial Product Supply [Member]
Disaggregation of Revenue [Line Items]
Net revenue									332.2	242.9
Biologics [Member] | Development Services [Member]
Disaggregation of Revenue [Line Items]
Net revenue									689.4	330.4
Biologics [Member] | Clinical Supply Services [Member]
Disaggregation of Revenue [Line Items]
Net revenue									0.0	0.0
Oral and Specialty Drug Delivery [Member]
Disaggregation of Revenue [Line Items]
Net revenue									675.9	597.7	503.3
Oral and Specialty Drug Delivery [Member] | Manufacturing & Commercial Product Supply [Member]
Disaggregation of Revenue [Line Items]
Net revenue									449.9	378.4
Oral and Specialty Drug Delivery [Member] | Development Services [Member]
Disaggregation of Revenue [Line Items]
Net revenue									226.0	219.3
Oral and Specialty Drug Delivery [Member] | Clinical Supply Services [Member]
Disaggregation of Revenue [Line Items]
Net revenue									0.0	0.0
Clinical Supply Services [Member]
Disaggregation of Revenue [Line Items]
Net revenue									345.0	321.4	$ 430.4
Clinical Supply Services [Member] | Manufacturing & Commercial Product Supply [Member]
Disaggregation of Revenue [Line Items]
Net revenue									0.0	0.0
Clinical Supply Services [Member] | Development Services [Member]
Disaggregation of Revenue [Line Items]
Net revenue									0.0	0.0
Clinical Supply Services [Member] | Clinical Supply Services [Member]
Disaggregation of Revenue [Line Items]
Net revenue									345.0	321.4
Total Catalent before inter-segment revenue elimination [Member]
Disaggregation of Revenue [Line Items]
Net revenue									3,104.5	2,531.6
Total Catalent before inter-segment revenue elimination [Member] | Manufacturing & Commercial Product Supply [Member]
Disaggregation of Revenue [Line Items]
Net revenue									1,737.5	1,565.9
Total Catalent before inter-segment revenue elimination [Member] | Development Services [Member]
Disaggregation of Revenue [Line Items]
Net revenue									1,022.0	644.3
Total Catalent before inter-segment revenue elimination [Member] | Clinical Supply Services [Member]
Disaggregation of Revenue [Line Items]
Net revenue									$ 345.0	$ 321.4