What is the process state (ID) in the output of the "ps" command?

Issue

What is the process state ID in the output of the ps command?

crash> ps -S
  RU: 5
  IN: 100
  ID: 66

crash> ps | grep ID | head
   PID    PPID  CPU       TASK        ST  %MEM     VSZ    RSS  COMM
      3      2   0  ffff8d91c778e200  ID   0.0       0      0  [rcu_gp]
      4      2   0  ffff8d91c778b100  ID   0.0       0      0  [rcu_par_gp]
      5      2   0  ffff8d91c778c980  ID   0.0       0      0  [kworker/0:0]
      6      2   0  ffff8d91c77be200  ID   0.0       0      0  [kworker/0:0H]
      7      2   0  ffff8d91c77bb100  ID   0.0       0      0  [kworker/u8:0]
      8      2   0  ffff8d91c77bc980  ID   0.0       0      0  [mm_percpu_wq]
     10      2   1  ffff8d91c77b9880  ID   0.0       0      0  [rcu_sched]
     19      2   1  ffff8d91c701b100  ID   0.0       0      0  [kworker/1:0H]
     25      2   2  ffff8d91c7043100  ID   0.0       0      0  [kworker/2:0H]

• What is the process state TASK_IDLE?