Share Repurchase - Additional Information (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended	6 Months Ended
	Mar. 31, 2016	Jun. 30, 2016	Jun. 30, 2015	Jan. 28, 2015
Accelerated Share Repurchases [Line Items]
Stock repurchase program, authorized amount				$ 500.0
Stock purchases, shares	2.2
Payment for share repurchase	$ 200.0	$ 200.0	$ 263.1
Evergreen Program
Accelerated Share Repurchases [Line Items]
Payment for share repurchase	103.0
Repurchase Program
Accelerated Share Repurchases [Line Items]
Payment for share repurchase	$ 97.0