REAL ID will be the minimum standard (some day) to go through TSA at US airports. Enhanced DL or passport also work.
Enhanced DL is a valid ID for entering Canada/Mexico via land or sea. Passport also works. AFAIK REAL ID is not sufficient for that task.
Passport is a valid ID for entering Canada/Mexico via air. AFAIK Enhanced DL is not sufficient for that task.
There may be alternate documents suitable for any of those tasks, e.g. NEXUS.
Enhanced DL is a valid ID for entering Canada/Mexico via land or sea. Passport also works. AFAIK REAL ID is not sufficient for that task.
Passport is a valid ID for entering Canada/Mexico via air. AFAIK Enhanced DL is not sufficient for that task.
There may be alternate documents suitable for any of those tasks, e.g. NEXUS.