Net Income Per Share - Computation of Net Income Per Share Amounts (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Apr. 30, 2022	Apr. 30, 2021
Numerator:
Net income	$ 146	$ 156
Denominator:
Denominator for basic net income per share—weighted average shares (in shares)	217	220
Effect of dilutive securities (in shares)	2	2
Denominator for dilutive net income per share (in shares)	219	222
Basic net income per share (in dollars per share)	$ 0.67	$ 0.71
Diluted net income per share (in dollars per share)	$ 0.67	$ 0.70