completion_cost_details is the USD cost breakdown for completion-side categories; per-category values are under raw. Omitted unless included in selects.
completion_token_details is the completion-side token breakdown by category; per-category counts are under raw. Omitted unless included in selects.
prompt_cost_details is the USD cost breakdown for prompt-side categories; per-category values are under raw. Omitted unless included in selects.
prompt_token_details is the prompt-side token breakdown by category; per-category counts are under nested raw. Omitted unless included in selects.
