Equity Incentive Plans - Stock Options and Restricted Stock Units, Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value	$ 469.1	$ 481.8	$ 293.9
Stock options vested, fair value	1.3	$ 4.3	$ 6.3
Share-based compensation cost not yet recognized	0.0
Share-based payment arrangement, nonvested award, excluding option, cost not yet recognized, amount	$ 5.1
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)	0	0
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, period for recognition	2 years 6 months 18 days
Share-based payment arrangement, nonvested award, excluding option, cost not yet recognized, amount	$ 768.0

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Gross number of share options (or share units) granted during the period.

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Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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