[en] The combination of high power deuterium neutral beam injection and operation with high current double-null divertor discharges has enabled increasingly high values of both toroidal and normalized beta (β_T and β_N respectively) to be obtained in the DIII-D tokamak. The highest achieved values are β_T = 9.3% and β_N = 5%-m-T/MA, obtained indifferent discharges. Here, β_T = (∫PdV/V)/(B²/μ ₀) is the volume average beta and β_N = β_T/(I/aB) where a is the minor radius of the discharge, B is the vacuum toroidal magnetic field at the geometric center of the discharge, P is the plasma pressure, V is the discharge volume, and I is the plasma current. It is expected that when the beta reaches a threshold value an ideal instability will occur, either the low toroidal mode number (n) ideal kink mode or the high-n, ideal ballooning mode. If all other obstacles to achieving high values of beta are overcome, it is generally postulated that the insurmountable limit to beta will be the stability threshold of one of these modes. According to Troyon-Sykes scaling, this limit to β_N is a constant (C_β) with a value which depends on the limiting ideal instability, plasma profiles, and wall stabilization. Previous tokamak experiments have found operational limits representing C_β values from 2.8 to 3.5, associated with several types of instabilities. Experimental data is presented in this paper that demonstrates that over a wide range of plasma current, in DIII-D the value of C_β is larger than 3.5