Employee Benefits - Schedule of Net Periodic Benefit Cost Components (Details) - USD ($)
$ in Millions |
12 Months Ended |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
| Other changes in plan assets and benefit obligations recognized in other comprehensive income: |
|
|
|
| Amortization of actuarial loss |
$ (4)
|
$ (7)
|
$ (7)
|
| Pension Plan Asset |
|
|
|
| Components of net periodic pension benefit cost and other postretirement benefit cost |
|
|
|
| Service cost |
28
|
34
|
33
|
| Interest cost |
82
|
76
|
80
|
| Expected return on plan assets |
(91)
|
(97)
|
(93)
|
| Amortization of prior service (credit) cost |
(3)
|
1
|
1
|
| Amortization of actuarial loss |
32
|
27
|
34
|
| Net periodic pension benefit cost |
48
|
41
|
55
|
| Other changes in plan assets and benefit obligations recognized in other comprehensive income: |
|
|
|
| Current year actuarial (gain) loss |
(8)
|
(60)
|
(7)
|
| Amortization of actuarial loss |
(4)
|
(7)
|
(7)
|
| Total recognized in other comprehensive income |
(12)
|
(67)
|
(14)
|
| Total recognized in net periodic benefit cost and other comprehensive income |
36
|
(26)
|
41
|
| Other Postretirement Benefit Cost |
|
|
|
| Components of net periodic pension benefit cost and other postretirement benefit cost |
|
|
|
| Service cost |
4
|
8
|
10
|
| Interest cost |
15
|
20
|
26
|
| Expected return on plan assets |
(18)
|
(26)
|
(26)
|
| Amortization of prior service (credit) cost |
(35)
|
(23)
|
(18)
|
| Amortization of actuarial loss |
3
|
3
|
10
|
| Net periodic pension benefit cost |
$ (31)
|
$ (18)
|
$ 2
|