Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net Income (Loss) Attributable to Parent	$ 431.3	$ 287.2
Denominator:
Denominator for basic earnings per share — weighted average common shares	368.3	375.1
Effect of dilutive securities:
Employee stock awards (shares)	5.1	5.0
Denominator for diluted earnings per share — adjusted weighted average common shares	373.4	380.1
Basic net income per common share attributable to Parent (in dollars per share)	$ 1.17	$ 0.77
Diluted net income per common share attributable to Parent (in dollars per share)	$ 1.16	$ 0.76