Debt and Credit Facilities - Debt and Related Weighted Average Contractual Interest Rates (Details) - USD ($) $ in Millions	Dec. 31, 2022	Mar. 31, 2022
Debt Instrument [Line Items]
Debt, Face value	$ 110,515	$ 109,449
Debt, Carrying value	$ 110,099	$ 109,152
Weighted average contractual interest rates	3.10%	1.23%
Unsecured notes and loans payable [Member]
Debt Instrument [Line Items]
Debt, Face value	$ 78,958	$ 82,542
Debt, Carrying value	$ 78,589	$ 82,288
Weighted average contractual interest rates	3.06%	1.30%
Secured notes and loans payable [Member]
Debt Instrument [Line Items]
Debt, Face value	$ 31,557	$ 26,907
Debt, Carrying value	$ 31,510	$ 26,864
Weighted average contractual interest rates	3.23%	1.01%