Income Taxes, U.S. statutory federal tax rate (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Differences between the U.S. statutory federal tax rate and the Company's effective income tax rate
U.S. statutory federal tax rate (as a percent)	35.00%	35.00%	35.00%
State and local taxes (as a percent)	0.20%	0.10%	0.10%
Foreign earnings and dividends taxed at different rates (as a percent)	(9.10%)	(9.70%)	(8.80%)
Valuation allowance (as a percent)	0.10%	0.70%	0.30%
Tax Act - transition tax (as a percent)	19.20%
Tax Act - remeasurement of deferred tax liabilities, net (as a percent)	(2.80%)
Tax Act - change in indefinite reinvestment assertion (as a percent)	13.10%
Excess tax benefits related to stock-based compensation (as a percent)	(4.90%)
Impact of acquisition-related expenses (as a percent)		0.50%	0.10%
Other, net (as a percent)	0.30%	0.40%	(0.10%)
Effective tax rate (as a percent)	51.10%	27.00%	26.60%