| 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | |||||||||||
| 
 | 
 | 
 | 
 | Accumulated other comprehensive income | 
 | 
 | 
 | ||||||||||||
|   | Capital stock of Covestro AG | Capital reserves of Covestro AG | Retained earnings incl. total income | Currency translation | Fair value of financial assets | Equity attributable to Covestro AG stockholders | Equity attributable to noncontrolling interest | Equity | |||||||||||
|   | € million | € million | € million | € million | € million | € million | € million | € million | |||||||||||
| 
 | |||||||||||||||||||
| Dec. 31, 20161 | 203 | 4,908 | (1,441) | 519 | – | 4,189 | 27 | 4,216 | |||||||||||
| Reacquisition of treasury shares | (2) | (141) | 
 | 
 | 
 | (143) | 
 | (143) | |||||||||||
| Dividend payments | 
 | 
 | (273) | 
 | 
 | (273) | (1) | (274) | |||||||||||
| 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | |||||||||||
| Income after income taxes | 
 | 
 | 2,009 | 
 | 
 | 2,009 | 8 | 2,017 | |||||||||||
| Other comprehensive income | 
 | 
 | (182) | (266) | 1 | (447) | (4) | (451) | |||||||||||
| Total comprehensive income | 
 | 
 | 1,827 | (266) | 1 | 1,562 | 4 | 1,566 | |||||||||||
| 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | |||||||||||
| Dec. 31, 20171 | 201 | 4,767 | 113 | 253 | 1 | 5,335 | 30 | 5,365 | |||||||||||
| thereof treasury shares | (2) | (141) | 
 | 
 | 
 | (143) | 
 | (143) | |||||||||||
| 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | |||||||||||
| Dec. 31, 20171 | 201 | 4,767 | 113 | 253 | 1 | 5,335 | 30 | 5,365 | |||||||||||
| Changes in accounting for initial application of new IFRS | 
 | 
 | 8 | 
 | (1) | 7 | 
 | 7 | |||||||||||
| Jan. 1, 2018 adjusted | 201 | 4,767 | 121 | 253 | – | 5,342 | 30 | 5,372 | |||||||||||
| Reacquisition and redemption of treasury shares | (18) | (1,295) | 
 | 
 | 
 | (1,313) | 
 | (1,313) | |||||||||||
| Issuance of treasury shares | 
 | 8 | 
 | 
 | 
 | 8 | 
 | 8 | |||||||||||
| Dividend payments | 
 | 
 | (436) | 
 | 
 | (436) | (5) | (441) | |||||||||||
| 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | |||||||||||
| Income after income taxes | 
 | 
 | 1,823 | 
 | 
 | 1,823 | 6 | 1,829 | |||||||||||
| Other comprehensive income | 
 | 
 | (152) | 70 | – | (82) | 2 | (80) | |||||||||||
| Total comprehensive income | 
 | 
 | 1,671 | 70 | – | 1,741 | 8 | 1,749 | |||||||||||
| 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | |||||||||||
| Dec. 31, 2018 | 183 | 3,480 | 1,356 | 323 | – | 5,342 | 33 | 5,375 | |||||||||||
| thereof treasury shares | – | (15) | 
 | 
 | 
 | (15) | 
 | (15) | |||||||||||