Long-Term Debt (Schedule of Future Minimum Lease Payments Related to Sale and Leaseback Transactions) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Long-Term Debt, Maturity, Year One	$ 2,375,720
Long-Term Debt, Maturity, Year Two	1,054,820
Long-Term Debt, Maturity, Year Three	2,158,446
Long-Term Debt, Maturity, Year Four	405,720
Long-Term Debt, Maturity, Year Five	916,822
Long-Term Debt, Fair Value	28,208,822	$ 25,181,802
Interest Expense, Debt	1,412,955	1,203,588	$ 1,046,164
Long-Term Debt	30,277,161	27,991,595
System Energy [Member]
Long-Term Debt, Maturity, Year One	0
Long-Term Debt, Maturity, Year Two	126,400
Long-Term Debt, Maturity, Year Three	325,000
Long-Term Debt, Maturity, Year Four	0
Long-Term Debt, Maturity, Year Five	0
Long-Term Debt, Fair Value	1,104,007	1,063,946
Interest Expense, Debt	72,148	48,121	$ 48,416
Long-Term Debt	1,088,703	$ 1,089,736
Grand Gulf [Member] | System Energy [Member]
Long-Term Debt, Maturity, Year One	17,188
Long-Term Debt, Maturity, Year Two	17,188
Long-Term Debt, Maturity, Year Three	17,188
Long-Term Debt, Maturity, Year Four	17,188
Long-Term Debt, Maturity, Year Five	17,188
Long-Term Debt, Maturity, after Year Five	103,125
Long-Term Debt, Fair Value	189,065
Interest Expense, Debt	154,952
Long-Term Debt	$ 34,113