The datasheet of Cmos ICs like the CD4017 from Texas Instruments has graphs that show the typical and minimum output current at different supply voltages and at different output voltages (the voltage that is limited by an LED).
With a 5V supply and a 1.8V red LED the output current is typically 3.5mA. The output transistor dissipates (5V - 1.8V) x 3.5mA= 11.2mW.
With a 9V supply and a 1.8V red LED the output current is typically 18mA. The output transistor dissipates (9V - 1.8V) x 18mA= 129.6mW.
With a 9V supply and a 3.2V white LED the current is typically 17mA. The output transistor dissipates (9V - 3.2V) x 17mA= 98.6mW.
The output transistors have a maximum allowed dissipation of 100mW so if the supply is 9V or more and the LED is 3.2V or less then a current-limiting resistor should be used to share the heat.
The CD4017 has only one output active at a time.