Employee Benefit Plans U.S and International Subsidiary Savings Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
U.S. savings plan
Defined Benefit Plan Disclosure [Line Items]
Expense for the U.S. and International subsidiary savings plan	$ 22	$ 21	$ 19
International subsidiary savings plans
Defined Benefit Plan Disclosure [Line Items]
Expense for the U.S. and International subsidiary savings plan	$ 17	$ 17	$ 16