Share-Based Compensation (Stock Option and Performance Share Units Grants) (Details) - SunCoke LTPEP - Stock Options - $ / shares |
12 Months Ended | ||
---|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Number of shares granted (shares) | 0 | 267,897 | 78,447 |
Weighted average exercise price (in USD per share) | $ 9.87 | $ 10.49 | |
Weighted-average fair value stock option (in dollars per share) | $ 4.09 | $ 5.38 |