Debt and Credit Facilities - Debt and Related Weighted Average Contractual Interest Rates (Details) - USD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023
Debt Instrument [Line Items]
Debt, Face value	$ 122,963	$ 112,170
Debt, Carrying value	$ 122,420	$ 111,685
Weighted average contractual interest rates	4.32%	3.56%
Unsecured notes and loans payable [Member]
Debt Instrument [Line Items]
Debt, Face value	$ 88,576	$ 79,393
Debt, Carrying value	$ 88,083	$ 78,949
Weighted average contractual interest rates	4.19%	3.48%
Secured notes and loans payable [Member]
Debt Instrument [Line Items]
Debt, Face value	$ 34,387	$ 32,777
Debt, Carrying value	$ 34,337	$ 32,736
Weighted average contractual interest rates	4.64%	3.76%