Originally it was to be the military industrial Congressional complex but a staffer had Ike shorten the phrase.
Pity, the original was more nuanced and accurate.
https://www.presidency.ucsb.edu/documents/farewell-radio-and-television-address-the-american-people
...In the councils of government, we must guard against the acquisition of unwarranted influence, whether sought or unsought, by the military-industrial complex. The potential for the disastrous rise of misplaced power exists and will persist...