Taxes on Income - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of beginning and ending amount of unrecognized tax benefits
Balance at beginning of year	$ 221	$ 162	$ 155
Additions based on tax positions related to the current year	23	48	24
Additions for tax positions of prior years	17	20	16
Reduction for tax positions of prior years	(32)	(3)	(15)
Reduction for settlements	(5)	(6)	(18)
Expiration of applicable statutes of limitations	(12)	0	0
Balance at end of year	$ 212	$ 221	$ 162