Debt and Credit Facilities - Debt and Related Weighted Average Contractual Interest Rates (Details) - USD ($) $ in Millions	Jun. 30, 2022	Mar. 31, 2022
Debt Instrument [Line Items]
Debt, Face value	$ 110,752	$ 109,449
Debt, Carrying value	$ 110,423	$ 109,152
Weighted average contractual interest rates	1.68%	1.23%
Unsecured notes and loans payable [Member]
Debt Instrument [Line Items]
Debt, Face value	$ 81,819	$ 82,542
Debt, Carrying value	$ 81,541	$ 82,288
Weighted average contractual interest rates	1.73%	1.30%
Secured notes and loans payable [Member]
Debt Instrument [Line Items]
Debt, Face value	$ 28,933	$ 26,907
Debt, Carrying value	$ 28,882	$ 26,864
Weighted average contractual interest rates	1.54%	1.01%