Income Taxes Narrative (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | 12 Months Ended | ||||
---|---|---|---|---|---|---|---|
May 31, 2018 |
Feb. 28, 2018 |
May 31, 2017 |
May 31, 2018 |
May 31, 2017 |
Aug. 31, 2019 |
Aug. 31, 2018 |
|
Income Tax Contingency [Line Items] | |||||||
Federal statutory rate (35% Prior to Enactment of Tax Act) | 35.00% | 35.00% | |||||
Provisional benefit from Tax Act | $ (7) | ||||||
Benefit from release of valuation allowance | $ (7) | ||||||
Effective tax rate | 21.70% | 0.90% | 5.70% | 2.50% | |||
Forecast | |||||||
Income Tax Contingency [Line Items] | |||||||
Federal statutory rate (35% Prior to Enactment of Tax Act) | 21.00% | 25.70% |