Supplemental Condensed Consolidating Financial Information - Consolidating Balance Sheet (Details) - USD ($) $ / shares in Units, $ in Millions | Jun. 30, 2018 | Dec. 31, 2017 |
Assets | | |
Cash and cash equivalents | $ 143 | $ 120.2 |
Receivables | 80.5 | 68.5 |
Inventories | 116.4 | 111 |
Income tax receivable | 4.8 | 4.8 |
Other current assets | 9.5 | 6.7 |
Advances to affiliate | 0 | 0 |
Total current assets | 354.2 | 311.2 |
Notes receivable from affiliate | 0 | 0 |
Properties, plants and equipment, net | 1,487.9 | 1,501.3 |
Goodwill | 76.9 | 76.9 |
Other intangible assets, net | 162.3 | 167.9 |
Deferred income taxes | 0 | 0 |
Deferred charges and other assets | 3 | 2.8 |
Total assets | 2,084.3 | 2,060.1 |
Liabilities and Equity | | |
Advances from affiliate | 0 | 0 |
Accounts payable | 134.8 | 115.5 |
Accrued liabilities | 44.4 | 53.2 |
Deferred revenue | 3.2 | 1.7 |
Current portion of long-term debt and financing obligation | 3.8 | 2.6 |
Interest payable | 4.1 | 5.4 |
Income taxes payable | 0 | 0 |
Total current liabilities | 190.3 | 178.4 |
Long-term debt and financing obligation | 860 | 861.1 |
Payable to affiliate | 0 | 0 |
Accrual for black lung benefits | 45.9 | 44.9 |
Retirement benefit liabilities | 27.1 | 28.2 |
Deferred income taxes | 257.8 | 257.8 |
Asset retirement obligations | 14.2 | 14 |
Other deferred credits and liabilities | 16.6 | 16.1 |
Total liabilities | 1,411.9 | 1,400.5 |
Equity | | |
Preferred stock, $0.01 par value. Authorized 50,000,000 shares; no issued shares at both June 30, 2018 and December 31, 2017 | 0 | 0 |
Common stock, $0.01 par value. Authorized 300,000,000 shares; issued 72,205,859 and 72,006,905 shares at June 30, 2018 and December 31, 2017, respectively | 0.7 | 0.7 |
Treasury stock, 7,477,657 shares at both June 30, 2018 and December 31, 2017 | (140.7) | (140.7) |
Additional paid-in capital | 487.3 | 486.2 |
Accumulated other comprehensive loss | (13.5) | (21.2) |
Retained earnings | 114.1 | 101.2 |
Equity investment eliminations | 0 | 0 |
Total SunCoke Energy, Inc. stockholders’ equity | 447.9 | 426.2 |
Noncontrolling interests | 224.5 | 233.4 |
Total equity | 672.4 | 659.6 |
Total liabilities and equity | $ 2,084.3 | $ 2,060.1 |
Preferred stock, par value (in dollars per share) | $ 0.01 | $ 0.01 |
Preferred stock, shares authorized (in shares) | 50,000,000 | 50,000,000 |
Preferred stock, shares issued (in shares) | 0 | 0 |
Common stock, par value (in dollars per share) | $ 0.01 | $ 0.01 |
Common stock, shares authorized (in shares) | 300,000,000 | 300,000,000 |
Common stock, shares, issued (in shares) | 72,205,859 | 72,006,905 |
Treasury stock, shares (in shares) | 7,477,657 | 7,477,657 |
Reportable Legal Entities | Issuer | | |
Assets | | |
Cash and cash equivalents | $ 0 | $ 0 |
Receivables | 0 | 0 |
Inventories | 0 | 0 |
Income tax receivable | 0 | 0 |
Other current assets | 0 | 0 |
Advances to affiliate | 0 | 0 |
Total current assets | 0 | 0 |
Notes receivable from affiliate | 0 | 0 |
Properties, plants and equipment, net | 0 | 0 |
Goodwill | 0 | 0 |
Other intangible assets, net | 0 | 0 |
Deferred income taxes | 7.1 | 7.1 |
Deferred charges and other assets | 0 | 0 |
Total assets | 7.1 | 7.1 |
Liabilities and Equity | | |
Advances from affiliate | 166.2 | 162.2 |
Accounts payable | 0 | 0 |
Accrued liabilities | 1.3 | 1.5 |
Deferred revenue | 0 | 0 |
Current portion of long-term debt and financing obligation | 1.1 | 0 |
Interest payable | 0.4 | 1.4 |
Income taxes payable | 1.2 | 1.9 |
Total current liabilities | 170.2 | 167 |
Long-term debt and financing obligation | 41.7 | 42.7 |
Payable to affiliate | 0 | 0 |
Accrual for black lung benefits | 0 | 0 |
Retirement benefit liabilities | 0 | 0 |
Deferred income taxes | 0 | 0 |
Asset retirement obligations | 0 | 0 |
Other deferred credits and liabilities | 3.9 | 3.7 |
Total liabilities | 215.8 | 213.4 |
Equity | | |
Preferred stock, $0.01 par value. Authorized 50,000,000 shares; no issued shares at both June 30, 2018 and December 31, 2017 | 0 | 0 |
Common stock, $0.01 par value. Authorized 300,000,000 shares; issued 72,205,859 and 72,006,905 shares at June 30, 2018 and December 31, 2017, respectively | 0.7 | 0.7 |
Treasury stock, 7,477,657 shares at both June 30, 2018 and December 31, 2017 | (140.7) | (140.7) |
Additional paid-in capital | 487.3 | 486.2 |
Accumulated other comprehensive loss | (13.5) | (21.2) |
Retained earnings | 114.2 | 101.2 |
Equity investment eliminations | (656.7) | (632.5) |
Total SunCoke Energy, Inc. stockholders’ equity | (208.7) | (206.3) |
Noncontrolling interests | 0 | 0 |
Total equity | (208.7) | (206.3) |
Total liabilities and equity | 7.1 | 7.1 |
Reportable Legal Entities | Guarantor Subsidiaries | | |
Assets | | |
Cash and cash equivalents | 115.5 | 103.6 |
Receivables | 12.3 | 17.1 |
Inventories | 13.9 | 9.1 |
Income tax receivable | 0 | 0 |
Other current assets | 6 | 4.6 |
Advances to affiliate | 266.8 | 245.8 |
Total current assets | 414.5 | 380.2 |
Notes receivable from affiliate | 89 | 89 |
Properties, plants and equipment, net | 56.9 | 59.8 |
Goodwill | 3.4 | 3.4 |
Other intangible assets, net | 1.3 | 1.7 |
Deferred income taxes | 0 | 0 |
Deferred charges and other assets | 2.7 | 2.3 |
Total assets | 567.8 | 536.4 |
Liabilities and Equity | | |
Advances from affiliate | 0 | 0 |
Accounts payable | 21.3 | 16.4 |
Accrued liabilities | 12.8 | 19.7 |
Deferred revenue | 0 | 0 |
Current portion of long-term debt and financing obligation | 0 | 0 |
Interest payable | 0 | 0 |
Income taxes payable | 86.9 | 81.4 |
Total current liabilities | 121 | 117.5 |
Long-term debt and financing obligation | 0 | 0 |
Payable to affiliate | 300 | 300 |
Accrual for black lung benefits | 12.3 | 11.8 |
Retirement benefit liabilities | 13.3 | 13.7 |
Deferred income taxes | 193.9 | 193.8 |
Asset retirement obligations | 0 | 0 |
Other deferred credits and liabilities | 6.4 | 6.4 |
Total liabilities | 646.9 | 643.2 |
Equity | | |
Preferred stock, $0.01 par value. Authorized 50,000,000 shares; no issued shares at both June 30, 2018 and December 31, 2017 | 0 | 0 |
Common stock, $0.01 par value. Authorized 300,000,000 shares; issued 72,205,859 and 72,006,905 shares at June 30, 2018 and December 31, 2017, respectively | 0 | 0 |
Treasury stock, 7,477,657 shares at both June 30, 2018 and December 31, 2017 | 0 | 0 |
Additional paid-in capital | 68.2 | 141 |
Accumulated other comprehensive loss | (2.3) | (2.2) |
Retained earnings | 505.9 | 475.6 |
Equity investment eliminations | (650.9) | (721.2) |
Total SunCoke Energy, Inc. stockholders’ equity | (79.1) | (106.8) |
Noncontrolling interests | 0 | 0 |
Total equity | (79.1) | (106.8) |
Total liabilities and equity | 567.8 | 536.4 |
Reportable Legal Entities | Non- Guarantor Subsidiaries | | |
Assets | | |
Cash and cash equivalents | 27.5 | 16.6 |
Receivables | 68.2 | 51.4 |
Inventories | 102.5 | 101.9 |
Income tax receivable | 92.9 | 88.1 |
Other current assets | 3.5 | 2.1 |
Advances to affiliate | 0 | 0 |
Total current assets | 294.6 | 260.1 |
Notes receivable from affiliate | 300 | 300 |
Properties, plants and equipment, net | 1,431 | 1,441.5 |
Goodwill | 73.5 | 73.5 |
Other intangible assets, net | 161 | 166.2 |
Deferred income taxes | 0 | 0 |
Deferred charges and other assets | 0.3 | 0.5 |
Total assets | 2,260.4 | 2,241.8 |
Liabilities and Equity | | |
Advances from affiliate | 100.6 | 83.6 |
Accounts payable | 113.5 | 99.1 |
Accrued liabilities | 30.3 | 32 |
Deferred revenue | 3.2 | 1.7 |
Current portion of long-term debt and financing obligation | 2.7 | 2.6 |
Interest payable | 3.7 | 4 |
Income taxes payable | 0 | 0 |
Total current liabilities | 254 | 223 |
Long-term debt and financing obligation | 818.3 | 818.4 |
Payable to affiliate | 89 | 89 |
Accrual for black lung benefits | 33.6 | 33.1 |
Retirement benefit liabilities | 13.8 | 14.5 |
Deferred income taxes | 71 | 71.1 |
Asset retirement obligations | 14.2 | 14 |
Other deferred credits and liabilities | 6.3 | 6 |
Total liabilities | 1,300.2 | 1,269.1 |
Equity | | |
Preferred stock, $0.01 par value. Authorized 50,000,000 shares; no issued shares at both June 30, 2018 and December 31, 2017 | 0 | 0 |
Common stock, $0.01 par value. Authorized 300,000,000 shares; issued 72,205,859 and 72,006,905 shares at June 30, 2018 and December 31, 2017, respectively | 0 | 0 |
Treasury stock, 7,477,657 shares at both June 30, 2018 and December 31, 2017 | 0 | 0 |
Additional paid-in capital | 626 | 641.9 |
Accumulated other comprehensive loss | (11.2) | (19) |
Retained earnings | 120.9 | 116.4 |
Equity investment eliminations | 0 | 0 |
Total SunCoke Energy, Inc. stockholders’ equity | 735.7 | 739.3 |
Noncontrolling interests | 224.5 | 233.4 |
Total equity | 960.2 | 972.7 |
Total liabilities and equity | 2,260.4 | 2,241.8 |
Combining and Consolidating Adjustments | | |
Assets | | |
Cash and cash equivalents | 0 | 0 |
Receivables | 0 | 0 |
Inventories | 0 | 0 |
Income tax receivable | (88.1) | (83.3) |
Other current assets | 0 | 0 |
Advances to affiliate | (266.8) | (245.8) |
Total current assets | (354.9) | (329.1) |
Notes receivable from affiliate | (389) | (389) |
Properties, plants and equipment, net | 0 | 0 |
Goodwill | 0 | 0 |
Other intangible assets, net | 0 | 0 |
Deferred income taxes | (7.1) | (7.1) |
Deferred charges and other assets | 0 | 0 |
Total assets | (751) | (725.2) |
Liabilities and Equity | | |
Advances from affiliate | (266.8) | (245.8) |
Accounts payable | 0 | 0 |
Accrued liabilities | 0 | 0 |
Deferred revenue | 0 | 0 |
Current portion of long-term debt and financing obligation | 0 | 0 |
Interest payable | 0 | 0 |
Income taxes payable | (88.1) | (83.3) |
Total current liabilities | (354.9) | (329.1) |
Long-term debt and financing obligation | 0 | 0 |
Payable to affiliate | (389) | (389) |
Accrual for black lung benefits | 0 | 0 |
Retirement benefit liabilities | 0 | 0 |
Deferred income taxes | (7.1) | (7.1) |
Asset retirement obligations | 0 | 0 |
Other deferred credits and liabilities | 0 | 0 |
Total liabilities | (751) | (725.2) |
Equity | | |
Preferred stock, $0.01 par value. Authorized 50,000,000 shares; no issued shares at both June 30, 2018 and December 31, 2017 | 0 | 0 |
Common stock, $0.01 par value. Authorized 300,000,000 shares; issued 72,205,859 and 72,006,905 shares at June 30, 2018 and December 31, 2017, respectively | 0 | 0 |
Treasury stock, 7,477,657 shares at both June 30, 2018 and December 31, 2017 | 0 | 0 |
Additional paid-in capital | (694.2) | (782.9) |
Accumulated other comprehensive loss | 13.5 | 21.2 |
Retained earnings | (626.9) | (592) |
Equity investment eliminations | 1,307.6 | 1,353.7 |
Total SunCoke Energy, Inc. stockholders’ equity | 0 | 0 |
Noncontrolling interests | 0 | 0 |
Total equity | 0 | 0 |
Total liabilities and equity | $ (751) | $ (725.2) |