Pension Benefits (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Payment for Pension Benefits				$ 2	$ 13
UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost		$ 5	$ 2	14	6
UNITED STATES | General and Administrative Expense [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		2	1	6	4
UNITED STATES | Other pension (income) expense [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost		9	10	26	30
Expected return on plan assets		(10)	(11)	(32)	(33)
Amortization of net loss		4	0	11	1
Amortization of prior service cost		0	2	3	4
Additional loss (gain) recognized due to settlements	[1]	$ 0	$ 1	$ 0	$ 3

[1] Loss is 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.