Face (par) amount of debt instrument at time of issuance.

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- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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- Definition

The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

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The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

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Debt - Narrative (Details) $ in Millions	3 Months Ended					6 Months Ended
Debt - Narrative (Details) $ in Millions	Sep. 30, 2020 GBP (£)	Jun. 30, 2020 USD ($)	Jun. 30, 2020 GBP (£)	Jun. 30, 2020 EUR (€)	Jun. 30, 2020 AUD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 GBP (£)	Sep. 30, 2020 EUR (€)
Debt Instrument [Line Items]
Repayments of debt						$ 1,476,000,000	$ 519,000,000
Senior notes \| Senior Notes Due 2024 and 2026
Debt Instrument [Line Items]
Principal amount		$ 1,000,000,000.0
Senior notes \| Senior Notes, Due 2024
Debt Instrument [Line Items]
Principal amount		$ 500,000,000				$ 500,000,000
Effective interest rate		4.00%				4.00%		4.00%	4.00%
Senior notes \| Senior Notes, Due 2026
Debt Instrument [Line Items]
Principal amount		$ 500,000,000				$ 500,000,000
Effective interest rate		4.13%				4.13%		4.13%	4.13%
Senior notes \| Senior notes due 2025
Debt Instrument [Line Items]
Principal amount \| £								£ 250,000,000
Effective interest rate						2.75%		2.75%	2.75%
Senior notes \| Senior notes due 2026
Debt Instrument [Line Items]
Principal amount \| €									€ 650,000,000
Effective interest rate						1.75%		1.75%	1.75%
Term loan \| Term Loan Payable, EUR, Due 2022-2023
Debt Instrument [Line Items]
Effective interest rate						0.65%		0.65%	0.65%
Repayments of debt \| €				€ 500,000,000
Term loan \| Term Loan Payable, GBP, Due 2022
Debt Instrument [Line Items]
Repayments of debt \| £	£ 300,000,000		£ 150,000,000
Term loan \| Term Loan Payable, AUD, Due 2022
Debt Instrument [Line Items]
Repayments of debt					$ 300
Term loan \| Term Loan Payable, USD, Due 2025
Debt Instrument [Line Items]
Repayments of debt		$ 100,000,000
Revolving credit facility \| Line of Credit
Debt Instrument [Line Items]
Proceeds from debt issuance		$ 2,500,000,000
Maximum borrowing capacity						$ 4,000,000,000.0
Repayments of debt						$ 2,750,000,000