Shareholders' Equity - Share Repurchase Programs (Details) - Ordinary Options - November 2016 Share Repurchase Program - USD ($) $ / shares in Units, shares in Millions	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018	Nov. 30, 2018	Nov. 30, 2016
Stock Activity [Line Items]
Total amount authorized for repurchase of shares under share repurchase program		$ 1,020,000,000.00		$ 300,000,000.0
Total amount additionally authorized for repurchase of shares under share repurchase program		$ 400,000,000.0	$ 320,000,000.0
Shares repurchased	$ 171,100,000
Shares repurchased (in shares)	1.3
Average price of shares repurchased (in dollars per share)	$ 131.17
Remaining amount authorized for repurchase of shares	$ 208,000,000.0