Leases - Supplemental Balance Sheet Information (Details) - USD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023
Operating Lease, Supplemental Balance Sheet Information [Abstract]
Operating right-of-use assets, net	$ 731	$ 909
Current operating lease liabilities	282	317
Non-current operating lease liabilities	497	648
Total operating lease liabilities	$ 779	$ 965
Finance Lease, Supplemental Balance Sheet Information [Abstract]
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Property and equipment, net of accumulated depreciation of $3,515 and $4,111	Property and equipment, net of accumulated depreciation of $3,515 and $4,111
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Short-term debt and current maturities of long-term debt	Short-term debt and current maturities of long-term debt
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Long-term debt excluding finance lease liabilities	Long-term debt excluding finance lease liabilities
ROU finance lease assets	$ 264	$ 424
Finance lease, liability, current	178	215
Finance lease, liability, noncurrent	242	287
Total finance lease liabilities	$ 420	$ 502