Pension Benefits (Details) - UNITED STATES - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost	$ 5	$ 4	$ 11	$ 9
General and Administrative Expense [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	2	4	4
Other pension (income) expense [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	8	8	16	17
Expected return on plan assets	(10)	(11)	(21)	(22)
Amortization of net loss	3	3	9	7
Amortization of prior service cost	$ 2	$ 2	$ 3	$ 3