Employee Benefits - Net Pension Cost (Benefit) for All Funded and Unfunded Plans (Details) - Pension Plans - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Interest cost on PBO	$ 8	$ 12	$ 17	$ 23
Expected return on plan assets	(9)	(12)	(19)	(24)
Amortization of losses	4	3	8	7
Settlement loss	4	0	8	0
Net pension cost	$ 7	$ 3	$ 14	$ 6