Stockholders' Equity (Common Stock Outstanding) (Details) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2019	May 31, 2021	May 31, 2020	May 31, 2021	May 31, 2020
Common stock outstanding:
Common stock outstanding, beginning balances (in shares)				150,330,358
Common stock outstanding, ending balance (in shares)		146,837,466		146,837,466
2020 Share Repurchase Program
Common stock outstanding:
Share repurchase program, amount authorized	$ 600,000,000.0
Capital allocation framework period	2 years
Number of shares repurchased (in shares)				11,900,000
Value of shares repurchased				$ 475,600,000
Share repurchase program, remaining amount available		$ 124,400,000		$ 124,400,000
Common stock
Common stock outstanding:
Common stock outstanding, beginning balances (in shares)	153,520,380	149,366,501	151,407,526	150,330,358	153,520,380
Shares issued upon exercise of stock options (in shares)		9,321	0	9,321	56,999
Shares issued under employee stock purchase plan (in shares)		0	0	771,548	595,717
Vesting of restricted stock (in shares)		12,787	13,234	2,253,923	2,252,846
Purchases of treasury stock under employee stock plans (in shares)		(3,436)	(2,808)	(613,715)	(619,931)
Treasury shares purchased (in shares)		(2,547,707)	(843,916)	(5,913,969)	(5,231,975)
Common stock outstanding, ending balance (in shares)		146,837,466	150,574,036	146,837,466	150,574,036