Stockholders' Equity (Capital Stock Activity) (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Ordinary shares, shares outstanding (in shares)	447.1	450.5
Stock Repurchased and Retired During Period, Shares	(4.0)
Ordinary Shares Issued
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Ordinary shares, shares outstanding (in shares)	447.1	450.5	465.1	119.2
Stock Issued During Period, Shares, Acquisitions			347.4
Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture	0.6	0.2	0.6
Treasury Stock, Shares, Retired		(14.8)	(2.1)
Ordinary Shares Held in Employee Benefit Trust
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Ordinary shares, shares outstanding (in shares)		0.1	0.1
Stock Issued During Period, Shares, New Issues	(0.1)		(0.1)
Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Ordinary shares, shares outstanding (in shares)				0.3
Stock Repurchased and Retired During Period, Shares			(0.3)
Treasury Stock, Shares, Acquired	4.0	14.8	2.1
Treasury Stock, Shares, Retired	(4.0)	(14.8)	(2.1)