Debt - Schedule of Outstanding Debt Net of Discounts and Fees, Weighted Average Contractual Interest Rates and Range of Contractual Interest Rates (Detail) - USD ($) $ in Millions	Jun. 30, 2025	Mar. 31, 2025
Debt Instrument [Line Items]
Unsecured debt	$ 51,725	$ 50,163
Total debt	$ 64,425	$ 62,547
Short-Term Debt
Debt Instrument [Line Items]
Contractual interest rate ranges (percentage)	4.58%	4.54%
Commercial paper
Debt Instrument [Line Items]
Unsecured debt	$ 6,751	$ 6,022
Weighted average contractual interest rate (percentage)	4.52%	4.36%
Commercial paper \| Minimum
Debt Instrument [Line Items]
Contractual interest rate ranges (percentage)	2.87%	2.73%
Commercial paper \| Maximum
Debt Instrument [Line Items]
Contractual interest rate ranges (percentage)	4.82%	4.70%
Related party debt
Debt Instrument [Line Items]
Unsecured debt	$ 1,000	$ 1,800
Weighted average contractual interest rate (percentage)	4.37%	4.59%
Related party debt \| Minimum
Debt Instrument [Line Items]
Contractual interest rate ranges (percentage)	4.37%	4.59%
Related party debt \| Maximum
Debt Instrument [Line Items]
Contractual interest rate ranges (percentage)	4.37%	4.60%
Bank loans
Debt Instrument [Line Items]
Unsecured debt	$ 2,663	$ 2,100
Weighted average contractual interest rate (percentage)	4.34%	4.56%
Bank loans \| Minimum
Debt Instrument [Line Items]
Contractual interest rate ranges (percentage)	3.55%	3.59%
Bank loans \| Maximum
Debt Instrument [Line Items]
Contractual interest rate ranges (percentage)	5.24%	5.27%
Public MTN program
Debt Instrument [Line Items]
Unsecured debt	$ 38,010	$ 37,153
Weighted average contractual interest rate (percentage)	3.87%	4.02%
Public MTN program \| Minimum
Debt Instrument [Line Items]
Contractual interest rate ranges (percentage)	0.30%	0.30%
Public MTN program \| Maximum
Debt Instrument [Line Items]
Contractual interest rate ranges (percentage)	5.85%	5.85%
Other debt
Debt Instrument [Line Items]
Unsecured debt	$ 3,301	$ 3,088
Weighted average contractual interest rate (percentage)	3.58%	3.53%
Other debt \| Minimum
Debt Instrument [Line Items]
Contractual interest rate ranges (percentage)	1.34%	1.34%
Other debt \| Maximum
Debt Instrument [Line Items]
Contractual interest rate ranges (percentage)	5.73%	5.73%
Secured debt
Debt Instrument [Line Items]
Secured debt	$ 12,700	$ 12,384
Weighted average contractual interest rate (percentage)	4.72%	4.77%
Secured debt \| Minimum
Debt Instrument [Line Items]
Contractual interest rate ranges (percentage)	1.88%	0.88%
Secured debt \| Maximum
Debt Instrument [Line Items]
Contractual interest rate ranges (percentage)	5.87%	5.87%

Contractual interest rate for funds borrowed, under the debt agreement.

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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.

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- Definition

Represents the aggregate of total long-term debt, including current maturities and short-term debt.

+ References

No definition available.

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- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

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- Definition

Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

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- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of uncollateralized debt obligations (with maturities initially due after one year or beyond the operating cycle if longer).

+ References

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