Share-Based Compensation - Summary of Stock Option Activity (Details) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Sep. 30, 2023 USD ($) $ / shares shares
Shares (in thousands)
Outstanding at beginning of period (in shares) | shares	2,246
Granted (in shares) | shares	233
Exercised (in shares) | shares	(539)
Forfeited (in shares) | shares	(14)
Canceled (in shares) | shares	(2)
Outstanding at end of period (in shares) | shares	1,924
Exercisable (in shares) | shares	1,554
Wtd. Avg. Exercise Price
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 186.72
Granted (in dollars per share) | $ / shares	259.82
Exercised (in dollars per share) | $ / shares	165.34
Forfeited (in dollars per share) | $ / shares	282.78
Canceled (in dollars per share) | $ / shares	350.76
Outstanding at end of period (in dollars per share) | $ / shares	200.03
Exercisable (in dollars per share) | $ / shares	$ 180.80
Wtd. Avg. Remaining Contractual Term (years)
Outstanding at end of period	5 years 7 months 6 days
Exercisable	4 years 10 months 24 days
Aggregate Intrinsic Value of In-The-Money Options (in millions)
Outstanding at end of period | $	$ 172.9
Exercisable | $	$ 165.4