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Debt - Additional Information (Detail) € in Millions	3 Months Ended		6 Months Ended
Debt - Additional Information (Detail) € in Millions	Mar. 31, 2022 USD ($)	Mar. 31, 2021 USD ($)	Mar. 31, 2022 USD ($)	Mar. 31, 2021 USD ($)	Mar. 31, 2022 EUR (€)	Nov. 24, 2021 EUR (€)	Sep. 30, 2021
Debt Instrument [Line Items]
Interest expense, net	$ 32,000,000	$ 32,000,000	$ 62,000,000	$ 63,000,000
Weighted-average interest rate of total debt	3.30%	3.70%	3.30%	3.70%	3.30%		3.20%
2.750% Senior Secured Notes due 2028 \| Acquisition Corp.
Debt Instrument [Line Items]
Interest rate	2.75%		2.75%		2.75%
Face or principal amount of debt instrument \| €					€ 325
3.875% Senior Secured Notes due 2030 \| Acquisition Corp.
Debt Instrument [Line Items]
Interest rate	3.875%		3.875%		3.875%
3.000% Senior Secured Notes due 2031
Debt Instrument [Line Items]
Interest rate	3.00%	3.00%	3.00%	3.00%	3.00%
3.000% Senior Secured Notes due 2031 \| Acquisition Corp.
Debt Instrument [Line Items]
Interest rate	3.00%		3.00%		3.00%
3.750% Senior Secured Notes due 2029
Debt Instrument [Line Items]
Interest rate	3.75%	3.75%	3.75%	3.75%	3.75%
3.750% Senior Secured Notes due 2029 \| Acquisition Corp.
Debt Instrument [Line Items]
Interest rate	3.75%		3.75%		3.75%	3.75%
Face or principal amount of debt instrument \| €						€ 540
2.250% Senior Secured Notes due 2031 \| Acquisition Corp.
Debt Instrument [Line Items]
Interest rate	2.25%		2.25%		2.25%
Face or principal amount of debt instrument \| €					€ 445
Senior Notes
Debt Instrument [Line Items]
Scheduled maturities of long-term debt in 2022	$ 0		$ 0
Scheduled maturities of long-term debt in 2023	0		0
Scheduled maturities of long-term debt in 2024	0		0
Scheduled maturities of long-term debt in 2025	0		0
Scheduled maturities of long-term debt, 2026	0		0
Scheduled maturities of long-term debt, 2027	360,000,000		360,000,000
Scheduled maturities of long-term debt, thereafter	$ 2,368,000,000		$ 2,368,000,000
Line of Credit \| Revolving Credit Facility
Debt Instrument [Line Items]
Debt instrument, covenant, total indebtedness to EBITDA ratio	3.50		3.50		3.50