Derivative Instruments and Hedging Activities - Schedule of Notional Amounts of Outstanding Derivative Positions (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Mar. 31, 2021	Sep. 30, 2020
Debt | Net Investment Hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	$ 2,543		$ 1,522
Forward exchange contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	2,735		2,519
Currency Swap | Net Investment Hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	1,958		2,971
Commodity forward contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	0		0
Fixed To Floating | Fair Value Hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	700		375
Interest rate swaps | Cash Flow Hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	$ 1,000		$ 1,500
Derivative, Notional Amount, Terminated		$ 500