Pension Benefits (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Payment for Pension Benefits		$ 9	$ 3
UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost		2	6
UNITED STATES | General and Administrative Expense [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		2	2
UNITED STATES | Other pension (income) expense [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost		10	9
Expected return on plan assets		(11)	(10)
Amortization of net loss		0	4
Amortization of prior service cost		1	1
Additional loss (gain) recognized due to settlements	[1]	$ (2)	$ (1)

[1] Losses are a result of settlement transactions which exceeded the sum of annual service and interest costs for the applicable plan. These losses were recorded in Other pension (income) expense.