Hybrid drive unit (101, 102) having an internal combustion engine, an electric machine, and a transmission, the transmission having an input shaft and at least a first countershaft and a second countershaft, it being possible for the internal combustion engine to be coupled directly to the input shaft via a disconnect clutch, six shiftable gear pairings being provided, namely a first gear pairing, a second gear pairing, a third gear pairing, a fourth gear pairing, a fifth gear pairing, and a sixth gear pairing, each having a gear wheel (Z1, Z3, Z5, Z7, Z9, Z11) arranged coaxially to the input shaft, the first gear pairing having a first gear wheel designed as a loose wheel and arranged coaxially to the input shaft, when viewed in an axial direction (a), the first shiftable gear pairing, a first shiftable element plane, the second shiftable gear pairing, the third shiftable gear pairing, the fourth shiftable gear pairing, a second shifting element plane, the fifth shiftable gear pairing, the sixth shiftable gear pairing, and an output gear plane being arranged one after the other in the specified sequence, characterized in that the first gear pairing has a second gearwheel designed as a loose wheel and arranged coaxially to the first countershaft, the electric machine being connected to the first gear pairing in such a way that torques, starting from the electric machine, can be directed into the transmission via the first gear pairing, the second gear pairing comprising a third gearwheel arranged coaxially to the input shaft and a fourth gear wheel arranged coaxially to the second countershaft, the third gear pairing comprising a fifth gear wheel arranged coaxially to the input shaft and a sixth gear wheel arranged coaxially to the second countershaft, the fourth gear pairing comprising a seventh gear wheel arranged coaxially to the input shaft and an eighth gear wheel arranged coaxially to the first countershaft, the fifth gear pairing comprising a ninth gear wheel arranged coaxially to the input shaft and a tenth gearwheel arranged coaxially to the second countershaft, and the sixth gear pairing comprising an eleventh gear wheel arranged coaxially to the input shaft and a twelfth gearwheel arranged coaxially to the first countershaft. the transmission having an input shaft and at least a first countershaft and a second countershaft, it being possible for the internal combustion engine to be coupled directly to the input shaft via a disconnect clutch, six shiftable gear pairings being provided, namely a first gear pairing, a second gear pairing, a third gear pairing, a fourth gear pairing, a fifth gear pairing, and a sixth gear pairing, each having a gear wheel (Z1, Z3, Z5, Z7, Z9, Z11) arranged coaxially to the input shaft, the first gear pairing having a first gear wheel designed as a loose wheel and arranged coaxially to the input shaft, when viewed in an axial direction (a), the first shiftable gear pairing, a first shiftable element plane, the second shiftable gear pairing, the third shiftable gear pairing, the fourth shiftable gear pairing, a second shifting element plane, the fifth shiftable gear pairing, the sixth shiftable gear pairing, and an output gear plane being arranged one after the other in the specified sequence, characterized in that the first gear pairing has a second gearwheel designed as a loose wheel and arranged coaxially to the first countershaft, the electric machine being connected to the first gear pairing in such a way that torques, starting from the electric machine, can be directed into the transmission via the first gear pairing, the second gear pairing comprising a third gearwheel arranged coaxially to the input shaft and a fourth gear wheel arranged coaxially to the second countershaft, the third gear pairing comprising a fifth gear wheel arranged coaxially to the input shaft and a sixth gear wheel arranged coaxially to the second countershaft, the fourth gear pairing comprising a seventh gear wheel arranged coaxially to the input shaft and an eighth gear wheel arranged coaxially to the first countershaft, the fifth gear pairing comprising a ninth gear wheel arranged coaxially to the input shaft and a tenth gearwheel arranged coaxially to the second countershaft, and the sixth gear pairing comprising an eleventh gear wheel arranged coaxially to the input shaft and a twelfth gearwheel arranged coaxially to the first countershaft.