Common Stock and Stock-Based Compensation Stockholders Equity (Details) - USD ($) $ in Millions	3 Months Ended							6 Months Ended
	Jun. 30, 2022		Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2021	Sep. 09, 2021	Sep. 30, 2020
Share Repurchases [Line Items]
Treasury Stock, Value, Acquired, Cost Method	$ 25.3					$ 290.8	$ 36.8
Share-based Payment Arrangement, Cash Used to Settle Award	2.9
2021-2022 Share Repurchase Program
Share Repurchases [Line Items]
Stock Repurchase Program, Authorized Amount									$ 250.0
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 47.8	[1]	$ 98.1	$ 98.1						$ 250.0
ASR Program
Share Repurchases [Line Items]
Stock Repurchase Program, Authorized Amount				$ 125.0
Treasury Stock, Shares, Acquired	760,602			3,300,000
Treasury Stock, Value, Acquired, Cost Method	$ 25.0
Special Share Repurchase Program
Share Repurchases [Line Items]
Treasury Stock, Shares, Acquired						8,100,000		8,100,000
Treasury Stock, Value, Acquired, Cost Method						$ 222.5		$ 222.5
Treasury Stock [Member]
Share Repurchases [Line Items]
Treasury Stock, Shares, Acquired	1,000,000.0					10,500,000	1,300,000
Treasury Stock, Value, Acquired, Cost Method	$ 25.3					$ 290.8	$ 36.8
Treasury Stock [Member] | 2021-2022 Share Repurchase Program
Share Repurchases [Line Items]
Treasury Stock, Shares, Acquired	1,760,462		0	5,155,491	0
Treasury Stock, Value, Acquired, Cost Method	$ 50.3		$ 0.0	$ 151.9	$ 0.0
Total Shares Repurchased Under Program	6,915,953
Total Shares Repurchased Under Program, Value	$ 202.2
Treasury Stock [Member] | 2020-2021 Share Repurchase Program
Share Repurchases [Line Items]
Treasury Stock, Shares, Acquired						10,500,000		11,800,000
Treasury Stock, Value, Acquired, Cost Method						$ 290.8		$ 327.6

[1] Share repurchases during the second quarter of 2022 included 760,602 shares at a cost of $25.0 million representing the final settlement of the ASR, which was funded in December 2021 but a portion of which remained outstanding as of December 31, 2021.