Fair value measurements- Additional Information (Details) $ in Billions	Feb. 29, 2024 USD ($)	Aug. 31, 2023
Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of long-term notes outstanding	$ 6.6
Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value of long-term notes outstanding	$ 6.0
Minimum | Level 3 | Variable Prepaid Forward, Lower Strike | Measurement Input, Price Volatility
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Measurement Input	0.254	0.232
Minimum | Level 3 | Variable Prepaid Forward, Upper Strike | Measurement Input, Price Volatility
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Measurement Input	0.201	0.181
Maximum | Level 3 | Variable Prepaid Forward, Lower Strike | Measurement Input, Price Volatility
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Measurement Input	0.292	0.247
Maximum | Level 3 | Variable Prepaid Forward, Upper Strike | Measurement Input, Price Volatility
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Measurement Input	0.226	0.191