Equity and Loss Per Share - Schedule of Non-Controlling Interests (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Noncontrolling Interest [Roll Forward]
Beginning of period (shares)	343,116,829	284,037,443	337,893,786	277,097,137
Issuance of Class A common stock (shares)	86,568,060	0	89,727,165	4,548,127
RSUs vested and exercise of options (shares)	16,651	699,456	2,080,589	3,091,635
End of period (shares)	429,701,540	284,736,899	429,701,540	284,736,899
Class A
Noncontrolling Interest [Roll Forward]
Beginning of period (shares)	323,741,458	133,031,072	318,480,601	122,842,474
Exchange of combined interests for Class A common stock (shares)	41,621	22,922	79,435	3,271,214
Issuance of Class A common stock (shares)	86,568,060	0	89,727,165	4,548,127
RSUs vested and exercise of options (shares)	16,651	699,456	2,080,589	3,091,635
End of period (shares)	410,367,790	133,753,450	410,367,790	133,753,450
Class A \| NuScale Corp Class A common stock
Controlling and Non Controlling Interest [Roll Forward]
Beginning of period	94.40%	46.80%	94.30%	44.30%
End of period	95.50%	47.00%	95.50%	47.00%
Class B
Noncontrolling Interest [Roll Forward]
Beginning of period (shares)	19,375,371	151,006,371	19,413,185	154,254,663
Exchange of combined interests for Class A common stock (shares)	(41,621)	(22,922)	(79,435)	(3,271,214)
End of period (shares)	19,333,750	150,983,449	19,333,750	150,983,449
Class B \| NuScale LLC Class B Units (NCI)
Controlling and Non Controlling Interest [Roll Forward]
Beginning of period	5.60%	53.20%	5.70%	55.70%
End of period	4.50%	53.00%	4.50%	53.00%