"whole of existence" is correct and usable in written English.
You can use it to talk about a large scope of time or all of something in existence. For example, you could say: "The problems facing humanity have been the same throughout the whole of existence."
In the summer of 1953, as Brecht worked on Turandot, events occurred that, he said, "alienated the whole of existence".
The title is a sideswipe at Nietzsche, who claimed saying "yes" to a single moment of being validated the whole of existence.
Auberon, an honest man, recalls that when he received the news, what he felt, mainly, was relief: "His death lifted a great brooding awareness not only from the house but from the whole of existence".
A question that, in poem and song, simply expresses a young lover's doubt -- "Is it true?" -- seems to be addressed to the whole of existence when it is voiced by the quartet.
Personally, after the ravages of the myth I am no longer astonished (as I once was) by — say — the Pasternak Soviet Writers' Union "trial," or the formation of any Nazi-type group that sees the whole of existence in its own patently cranky terms.
Holden's famous idiom, which throws a curse over almost the whole of existence and casually thrusts even the youngest and most innocent like "old Phoebe" and "old Stradlater" into their dotage, is as much or more that of the barracks as of the dormitory, the ideal medium for a war veteran who has found a way to impart the real quality of his experience.
As specialists, we feel ourselves absolved from whole realms of existence.
It has, finally, something to do with our whole manner of existence.
They overlooked the fact that the chairman of the Appropriations Committee, Senator Robert Byrd, regarded this practice as the whole point of existence.
In the whole rest of existence, weird and imperfect things can be beautiful and we pay money to look at them in art museums and hear them live in concert, but in being a woman, only this ONE THING equals beauty.
Moreover, the very same awareness engages the first of the aforementioned transitions too: there is a sense in which the possibility of my not existing encompasses the whole of my existence (Hinman 1978, 201), and my awareness of that possibility illuminates me, qua Dasein, in my totality.
