Earnings Per Share And Shareholder's Equity (Details) - USD ($) $ / shares in Units, shares in Millions	1 Months Ended	12 Months Ended
	Oct. 31, 2015	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Oct. 31, 2018	Oct. 30, 2015
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, period in force	3 years
Stock repurchase program, authorized amount					$ 1,000,000,000.0	$ 2,000,000,000.0
Average repurchase price (in USD per share)			$ 77.93	$ 71.72
Payments for repurchase of equity			$ 400,000,000.0	$ 191,500,000
Common Stock
Equity, Class of Treasury Stock [Line Items]
Repurchases of ordinary shares, shares		0.0	5.1	2.7