Pension and Other Postretirement Benefits - Expenses (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
|
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | |||
| Pension and other postretirement benefits cost | $ 87 | $ 103 | $ 111 |
| Pension benefits | |||
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | |||
| Net periodic benefit cost | 68 | 82 | 5 |
| Multiemployer contribution expense | 0 | 0 | 61 |
| Cost allocation | 0 | (1) | 20 |
| Pension and other postretirement benefits cost | 68 | 81 | 86 |
| Actuarial loss attributable to change in discount rate used to determine benefit obligation | (130) | 370 | |
| Other postretirement benefits | |||
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | |||
| Net periodic benefit cost | 19 | 22 | 0 |
| Multiemployer contribution expense | 0 | 0 | 21 |
| Cost allocation | 0 | 0 | 4 |
| Pension and other postretirement benefits cost | $ 19 | $ 22 | $ 25 |