Derivative Instruments - Narrative (Details) $ in Millions	3 Months Ended	6 Months Ended
Sep. 30, 2021 USD ($)	Sep. 30, 2021 USD ($) counterparty	Mar. 31, 2021 USD ($)
Derivative [Line Items]
Foreign currency cash flow hedge gain to be reclassified during next 12 months	$ 10	$ 10
Number of counterparties with concentration of credit risk \| counterparty		7
Maximum exposure to loss		$ 5
Designated as Hedging Instrument
Derivative [Line Items]
Pretax gain (loss) on derivatives designated for hedge accounting included other comprehensive income	11	10
Designated as Hedging Instrument \| Cash Flow Hedging \| Foreign Currency Forward Contracts
Derivative [Line Items]
Notational amount of derivative	537	537	$ 546
Designated as Hedging Instrument \| Net Investment Hedging \| Foreign Currency Denominated Debt
Derivative [Line Items]
Notational amount of derivative	300	300	800
Pretax gain (loss) on derivatives designated for hedge accounting included other comprehensive income	(12)	(5)
Not Designated as Hedging Instrument \| Foreign Currency Forward Contracts
Derivative [Line Items]
Notational amount of derivative	$ 2,500	$ 2,500	$ 2,100

Concentration Risk, Credit Risk, Financial Instrument, Number of Counterparties

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- Definition

Maximum amount of loss due to credit risk that, based on the gross fair value of the financial instrument, the entity would incur if parties to the financial instruments that make up the concentration failed completely to perform according to the terms of the contracts and the collateral or other security, if any, for the amount due proved to be of no value to the entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123594938&loc=d3e13537-108611

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- Definition

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.

+ References

No definition available.

+ Details

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- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5579245-113959

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- Definition

The estimated net amount of unrealized gains or losses on foreign currency cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121549185&loc=d3e80748-113994

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- Definition

Amount, before tax and after reclassification, of gain (loss) from derivative instrument designated and qualifying cash flow hedge included in assessment of hedge effectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=124509347&loc=SL7669646-108580

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=124509347&loc=d3e637-108580

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