Treasury Stock (Details) - USD ($)		1 Months Ended	3 Months Ended		9 Months Ended
	Jan. 30, 2020	Aug. 31, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jan. 31, 2020
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount							$ 1,000,000,000.00
Available to repurchase common stock			$ 714,100,000		$ 714,100,000
Amount expended on share repurchases in open market transactions				$ 103,905,000	$ 199,903,000	$ 353,904,000
Number of shares withheld to satisfy minimum tax withholding obligations			25,826	44,829	765,426	742,946
Payment for tax withholding related to vested stock units			$ 3,700,000	$ 4,200,000	$ 104,800,000	$ 74,800,000
Open Market Purchases [Member]
Equity, Class of Treasury Stock [Line Items]
Amount expended on share repurchases in open market transactions			$ 0	$ 103,900,000	$ 199,900,000	$ 353,900,000
Stock repurchases net (shares)				1,130,100	1,731,500	3,640,982
Average per share price on share repurchases in open market transactions (in dollars per share)				$ 91.94	$ 115.45	$ 97.20
ASR Counterparty [Member]
Equity, Class of Treasury Stock [Line Items]
Amount expended on share repurchases in open market transactions	$ 1,000,000,000.00
Stock repurchases net (shares)	6,500,000	800,000