Fair value measurement recurring basis (Detail) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Jun. 30, 2024
Fair Value Disclosures [Abstract]
Trading Securities at Fair Value	$ 3		$ 1
Interest Rate Cash Flow Hedge Asset at Fair Value	23		36
Interest Rate Cash Flow Hedge Liability at Fair Value			36
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities at Fair Value	3		1
Interest Rate Cash Flow Hedge Asset at Fair Value	23		36
Interest Rate Cash Flow Hedge Liability at Fair Value			36
Payments for (Proceeds from) Businesses and Interest in Affiliates	17	$ 0
Fair Value, Inputs, Level 1 [Member]
Fair Value Disclosures [Abstract]
Trading Securities at Fair Value	3		1
Interest Rate Cash Flow Hedge Asset at Fair Value	0		0
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities at Fair Value	3		1
Interest Rate Cash Flow Hedge Asset at Fair Value	0		0
Fair Value, Inputs, Level 2 [Member]
Fair Value Disclosures [Abstract]
Trading Securities at Fair Value	0		0
Interest Rate Cash Flow Hedge Asset at Fair Value	23		36
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities at Fair Value	0		0
Interest Rate Cash Flow Hedge Asset at Fair Value	23		36
Fair Value, Inputs, Level 3 [Member]
Fair Value Disclosures [Abstract]
Trading Securities at Fair Value	0		0
Interest Rate Cash Flow Hedge Asset at Fair Value	0		0
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities at Fair Value	0		0
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 0		$ 0

Catalent, Inc. 10-Q