Taxes on Income - Tax reform estimates (Details) $ in Millions		3 Months Ended		9 Months Ended
	Jan. 01, 2018	Sep. 30, 2018	Dec. 31, 2017 USD ($)	Sep. 30, 2018
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Increase in effective tax rate due to write-off of goodwill		37.7		14.2
Effect of Tax Cuts and Jobs Act
Income tax expense for the estimated impact of the Tax Act adjustments			$ 83
Provisional increase of tax expense, change in tax rate effect on tax asset position			52
Effective income tax rate	21.00%
Provisional increase of transition tax expense			$ 31