Defined Benefit Plans - Schedule of Assumptions Used (Detail) |
12 Months Ended | ||
---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
Weighted-Average Assumptions Used to Determine Net Cost for Years Ended December 31: | |||
Expected long-term rate of return on plan assets | 6.40% | ||
Pension Benefits [Member] | |||
Weighted-Average Assumptions Used to Determine Benefit Obligations at December 31: | |||
Discount rate | 3.80% | 4.30% | 4.60% |
Rate of compensation increase | 4.00% | 4.00% | |
Weighted-Average Assumptions Used to Determine Net Cost for Years Ended December 31: | |||
Discount rate | 4.30% | 4.60% | 4.20% |
Expected long-term rate of return on plan assets | 6.40% | 6.60% | 6.80% |
Rate of compensation increase | 4.00% | 4.00% | |
Postretirement Benefits [Member] | |||
Weighted-Average Assumptions Used to Determine Benefit Obligations at December 31: | |||
Discount rate | 3.40% | 3.40% | 4.10% |
Weighted-Average Assumptions Used to Determine Net Cost for Years Ended December 31: | |||
Discount rate | 3.40% | 4.10% | 3.50% |