v3.26.1
Changes in Capital Structure - Changes in NRG's Common Stock Issued and Outstanding (Details) - shares
 1 Months Ended 6 Months Ended
Jul. 08, 2025
Jul. 31, 2026
Jun. 30, 2026
Schedule of Stock by Class, Equity [Roll Forward]      
Preferred, Balance as of beginning of period (in shares)   650,000 650,000
Preferred, Balance as of end of period (in shares)     650,000
Common, Balance as of beginning of period (in shares)   225,198,900 199,828,615
Treasury, Balance as of beginning of period (in shares)   (14,890,998) (9,452,008)
Common, Outstanding, as of beginning of period (in shares)   210,307,902 190,376,607
Shares repurchased (in shares)     (5,865,179)
Shares issued for the acquisition of the LSP Portfolio (in shares)     24,250,000
Retirement of treasury stock (in shares) (224,585)    
Common, Balance as of end of period (in shares)     225,198,900
Treasury, Balance as of end of period (in shares)     (14,890,998)
Common, Outstanding, as of end of period (in shares)     210,307,902
Subsequent Event      
Schedule of Stock by Class, Equity [Roll Forward]      
Shares repurchased (in shares)   (104,270)  
Common, Outstanding, as of end of period (in shares)   210,210,483  
Shares issued under LTIPs      
Schedule of Stock by Class, Equity [Roll Forward]      
Shares issued under LTIPs (in shares)     1,461,185
Shares issued under LTIPs | Subsequent Event      
Schedule of Stock by Class, Equity [Roll Forward]      
Shares issued under LTIPs (in shares)   6,851  
Shares issued under ESPP      
Schedule of Stock by Class, Equity [Roll Forward]      
Shares issued under ESPP (in shares)     85,289
Preferred Stock      
Schedule of Stock by Class, Equity [Roll Forward]      
Preferred, Balance as of beginning of period (in shares)   650,000 650,000
Preferred, Balance as of end of period (in shares)     650,000
Preferred Stock | Subsequent Event      
Schedule of Stock by Class, Equity [Roll Forward]      
Preferred, Balance as of end of period (in shares)   650,000  
Common Stock      
Schedule of Stock by Class, Equity [Roll Forward]      
Common, Balance as of beginning of period (in shares)   225,198,900 199,828,615
Shares issued for the acquisition of the LSP Portfolio (in shares)     24,250,000
Retirement of treasury stock (in shares)     (340,900)
Common, Balance as of end of period (in shares)     225,198,900
Common Stock | Subsequent Event      
Schedule of Stock by Class, Equity [Roll Forward]      
Common, Balance as of end of period (in shares)   225,205,751  
Common Stock | Shares issued under LTIPs      
Schedule of Stock by Class, Equity [Roll Forward]      
Shares issued under LTIPs (in shares)     1,461,185
Common Stock | Shares issued under LTIPs | Subsequent Event      
Schedule of Stock by Class, Equity [Roll Forward]      
Shares issued under LTIPs (in shares)   6,851  
Treasury Stock      
Schedule of Stock by Class, Equity [Roll Forward]      
Treasury, Balance as of beginning of period (in shares)   (14,890,998) (9,452,008)
Shares repurchased (in shares)     (5,865,179)
Retirement of treasury stock (in shares)     340,900
Treasury, Balance as of end of period (in shares)     (14,890,998)
Treasury Stock | Subsequent Event      
Schedule of Stock by Class, Equity [Roll Forward]      
Shares repurchased (in shares)   (104,270)  
Treasury, Balance as of end of period (in shares)   (14,995,268)  
Treasury Stock | Shares issued under ESPP      
Schedule of Stock by Class, Equity [Roll Forward]      
Shares issued under ESPP (in shares)     85,289