Stockholders' Equity - Share-based Compensation, Stock Options, Activity (Details) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Apr. 30, 2025 USD ($) $ / shares shares
Outstanding Stock Options (in millions)
Beginning balance (in shares) | shares	8
Exercised (in shares) | shares	(1)
Ending balance (in shares) | shares	7
Outstanding Stock Options, Vested or expected to vest (in shares) | shares	7
Outstanding Stock Options, Exercisable (in shares) | shares	6
Weighted- Average Exercise Price
Beginning balance (in dollars per share) | $ / shares	$ 198.89
Exercised (in dollars per share) | $ / shares	179.79
Ending balance (in dollars per share) | $ / shares	204.09
Weighted-Average Exercise Price, Vested or expected to vest (in dollars per share) | $ / shares	203.33
Weighted-Average Exercise Price, Exercisable (in dollars per share) | $ / shares	$ 192.81
Aggregate Intrinsic Value (in millions)
Balance | $	$ 527
Vested or expected to vest | $	522
Exercisable | $	$ 441