Stockholders' Equity (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Jul. 28, 2020	Oct. 22, 2019	Feb. 28, 2017
Class of Stock [Line Items]
Treasury Stock, Shares, Acquired	2.3	0.3	3.6	0.4
Treasury Stock, Value, Acquired, Cost Method	$ 253.7	$ 37.6	$ 360.8	$ 48.9
Common Stock
Class of Stock [Line Items]
Repurchase authorization amount						$ 1,000.0	$ 1,000.0
Subsequent Event
Class of Stock [Line Items]
Repurchase authorization amount					$ 1,500.0
Subsequent Event | Common Stock
Class of Stock [Line Items]
Remaining authorized repurchase amount					$ 2,174.7